[fenix] Close https://github.com/mozilla-mobile/fenix/issues/26041: Remove un-needed Nimbus workaround

This workaround was temporary and is not needed with the Nimbus groovy
plugin updates in Android Components.

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

@@ -434,15 +434,6 @@ open class FenixApplication : LocaleAwareApplication(), Provider {
     private fun setupNimbusObserver(nimbus: Observable<NimbusInterface.Observer>) {
         nimbus.register(object : NimbusInterface.Observer {
             override fun onUpdatesApplied(updated: List<EnrolledExperiment>) {
-                // To workaround a caching bug in Nimbus that appears when we try to query an
-                // experiment **before** `FxNimbus.initialize` is called we need to set the `api`
-                // value again so that we can still access the NimbusApi that is wrapped
-                // in `FxNimbus.initialize.getSdk`.
-                //
-                // We set this value here to minimize the race between setting the `api` value and
-                // the callers of FxNimbus.
-                // See: https://github.com/mozilla/application-services/issues/5075
-                FxNimbus.api = components.analytics.experiments
                 onNimbusStartupAndUpdate()
             }
         })