[fenix] For https://github.com/mozilla-mobile/fenix/issues/6464: Add ReleaseChannel.isDebug.

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

@@ -15,6 +15,16 @@ enum class ReleaseChannel {
             else -> true
         }
 
+    /**
+     * True if this is a debug release channel, false otherwise.
+     *
+     * This constant should often be used instead of [BuildConfig.DEBUG], which indicates
+     * if the `debuggable` flag is set which can be true even on released channel builds
+     * (e.g. performance).
+     */
+    val isDebug: Boolean
+        get() = !this.isReleased
+
     val isReleaseOrBeta: Boolean
         get() = when (this) {
             FenixProduction -> true