Fix toolbar height and fade in.

app/src/main/java/org/thoughtcrime/securesms/mediapreview/MediaPreviewV2Fragment.kt

@@ -185,13 +185,12 @@ class MediaPreviewV2Fragment : LoggingFragment(R.layout.fragment_media_preview_v
   private fun initializeFullScreenUi() {
     fullscreenHelper.configureToolbarLayout(binding.toolbarCutoutSpacer, binding.toolbar)
     fullscreenHelper.showAndHideWithSystemUI(requireActivity().window, binding.toolbarLayout, binding.mediaPreviewDetailsContainer)
-    fullscreenHelper.hideSystemUI()
 
     lifecycleDisposable += viewModel.state.map {
       it.isInSharedAnimation to it.loadState
     }.distinctUntilChanged().subscribe { (isInSharedAnimation, loadState) ->
       if (!isInSharedAnimation && loadState == MediaPreviewV2State.LoadState.MEDIA_READY) {
-        fullscreenHelper.showSystemUI()
+        binding.toolbarLayout.animate().alpha(1f)
       }
     }
   }

app/src/main/res/layout/fragment_media_preview_v2.xml

@@ -54,6 +54,7 @@
         android:id="@+id/toolbar_layout"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
+        android:alpha="0"
         android:background="@color/signal_dark_colorSurface_87"
         app:elevation="0dp">
 
@@ -66,8 +67,9 @@
         <com.google.android.material.appbar.MaterialToolbar
             android:id="@+id/toolbar"
             android:layout_width="match_parent"
-            android:layout_height="?attr/actionBarSize"
+            android:layout_height="@dimen/signal_m3_toolbar_height"
             android:background="@android:color/transparent"
+            android:minHeight="@dimen/signal_m3_toolbar_height"
             android:theme="?actionBarStyle"
             app:navigationIcon="@drawable/ic_arrow_left_white_24" />