[fenix] Remove direct A-S dependency; switch to using 'full' megazord

As far as I can tell, we never actually exercise the a-s libraries in Fenix tests currently (this was one of the presumed reasons for having a direct dependency).
In a different branch I've started work on adding end-to-end tests, but currently that's blocked on trying to figure out to load native libraries in tests (somehow, fenix's setup is different than what we have in A-C, not yet clear to me in what way).

Another reason for a direct dependency (i think) is that we needed it to configure a `fenix` megazord. This could be solved via a `support-megazord-fenix` a-c component that provides the correct transient dependencies,
but we can also just switch to use the `full` megazord instead, which is essentially what fenix megazord is at this point. A-S team wants to remove the fenix megazord, so this will help. This is what this patch does.

app/build.gradle

@@ -530,22 +530,7 @@ dependencies {
     }
 
     testImplementation 'org.apache.maven:maven-ant-tasks:2.1.3'
-    // For production builds, the native code for all `org.mozilla.appservices`
-    // dependencies gets compiled together into a single "megazord" build, and
-    // different megazords are published for different subsets of features. Ref
-    // https://mozilla.github.io/application-services/docs/applications/consuming-megazord-libraries.html
-    // We want to use the one that's specifically designed for Fenix.
-    implementation Deps.fenix_megazord
-    testImplementation Deps.fenix_megazord_forUnitTests
     implementation Deps.mozilla_support_rusthttp
-    modules {
-        module('org.mozilla.appservices:full-megazord') {
-            replacedBy('org.mozilla.appservices:fenix-megazord', 'prefer the fenix megazord, to reduce final application size')
-        }
-        module('org.mozilla.appservices:fenix-megazord') {
-            replacedBy('org.mozilla.appservices:fenix-megazord-forUnitTests', 'prefer the forUnitTests variant if present')
-        }
-    }
 
     testImplementation Deps.mockito_core
     androidTestImplementation Deps.mockito_android
@@ -654,11 +639,6 @@ ext.gleanGenerateMarkdownDocs = true
 ext.gleanDocsDirectory = "$rootDir/docs"
 apply from: 'https://github.com/mozilla-mobile/android-components/raw/' + glean_android_components_tag + '/components/service/glean/scripts/sdk_generator.gradle'
 
-// For production builds, the native code for all `org.mozilla.appservices` dependencies gets compiled together
-// into a single "megazord" build, and different megazords are published for different subsets of features.
-// Ref https://mozilla.github.io/application-services/docs/applications/consuming-megazord-libraries.html
-// Substitute all appservices dependencies with an appropriate megazord.
-
 afterEvaluate {
 
     // Format test output. Ported from AC #2401

app/src/main/java/org/mozilla/fenix/FenixApplication.kt

@@ -191,10 +191,10 @@ open class FenixApplication : LocaleAwareApplication() {
     /**
      * Initiate Megazord sequence! Megazord Battle Mode!
      *
-     * The application-services combined libraries are known as the "megazord". The default megazord
+     * The application-services combined libraries are known as the "megazord". We use the default `full`
-     * contains several features that fenix doesn't need, and so we swap out with a customized fenix-specific
+     * megazord - it contains everything that fenix needs, and (currently) nothing more.
-     * version of the megazord. The best explanation for what this is, and why it's done is the a-s
+     *
-     * documentation on the topic:
+     * Documentation on what megazords are, and why they're needed:
      * - https://github.com/mozilla/application-services/blob/master/docs/design/megazords.md
      * - https://mozilla.github.io/application-services/docs/applications/consuming-megazord-libraries.html
      */

buildSrc/src/main/java/Dependencies.kt

@@ -33,13 +33,6 @@ object Versions {
     const val google_material = "1.1.0"
 
     const val mozilla_android_components = "34.0.0-SNAPSHOT"
-    // Note that android-components also depends on application-services,
-    // and in fact is our main source of appservices-related functionality.
-    // The version number below tracks the application-services version
-    // that we depend on directly for the fenix-megazord (and for it's
-    // forUnitTest variant), and it's important that it be kept in
-    // sync with the version used by android-components above.
-    const val mozilla_appservices = "0.50.0"
 
     const val mozilla_glean = "25.0.0"
 
@@ -207,9 +200,6 @@ object Deps {
     const val androidx_junit = "androidx.test.ext:junit:${Versions.androidx_test_ext}"
     const val androidx_test_core = "androidx.test:core:${Versions.androidx_testing}"
 
-    const val fenix_megazord = "org.mozilla.appservices:fenix-megazord:${Versions.mozilla_appservices}"
-    const val fenix_megazord_forUnitTests = "org.mozilla.appservices:fenix-megazord-forUnitTests:${Versions.mozilla_appservices}"
-
     const val google_ads_id = "com.google.android.gms:play-services-ads-identifier:${Versions.google_ads_id_version}"
 
     const val lottie = "com.airbnb.android:lottie:${Versions.airbnb_lottie}"