Puts login selection behind a nightly feature flag

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

@@ -50,4 +50,9 @@ object FeatureFlags {
      * Enables viewing downloads in browser.
      */
     val viewDownloads = Config.channel.isNightlyOrDebug
+
+    /**
+     * Enables selecting from multiple logins.
+     */
+    val loginSelect = Config.channel.isNightlyOrDebug
 }

app/src/main/java/org/mozilla/fenix/browser/BaseBrowserFragment.kt

@@ -488,7 +488,7 @@ abstract class BaseBrowserFragment : Fragment(), UserInteractionHandler, Session
                     onNeedToRequestPermissions = { permissions ->
                         requestPermissions(permissions, REQUEST_CODE_PROMPT_PERMISSIONS)
                     },
-                    loginPickerView = loginSelectBar,
+                    loginPickerView = if (FeatureFlags.loginSelect) loginSelectBar else null,
                     onManageLogins = {
                         browserAnimator.captureEngineViewAndDrawStatically {
                             val directions =