Migrate to androidx-media3 video player (#3857)

Behaviour is consistent with previous player except that:

- Swapping apps while a video is playing, and then returning to Tusky,
will keep the seek position in the video instead of returning to the
start
- The controls/media description can be shown by tapping anywhere, not
just on the video itself
- The media description is on-screen for the same duration as the player
controls (5 seconds here, 3 seconds in the previous code)
- The user has options to control the playback speed
- Rotating the device does not squash/stretch the video
- Show the media preview when playing audio-only files

Fixes https://github.com/tuskyapp/Tusky/issues/3329,
https://github.com/tuskyapp/Tusky/issues/3141,
https://github.com/tuskyapp/Tusky/issues/3126,
https://github.com/tuskyapp/Tusky/issues/2753,
https://github.com/tuskyapp/Tusky/issues/3508,
https://github.com/tuskyapp/Tusky/issues/3291

---------

Co-authored-by: mcc <andi.m.mcclure@gmail.com>

app/src/main/java/com/keylesspalace/tusky/ViewMediaActivity.kt

@@ -59,6 +59,8 @@ import com.keylesspalace.tusky.pager.SingleImagePagerAdapter
 import com.keylesspalace.tusky.util.getTemporaryMediaFilename
 import com.keylesspalace.tusky.util.viewBinding
 import com.keylesspalace.tusky.viewdata.AttachmentViewData
+import dagger.android.DispatchingAndroidInjector
+import dagger.android.HasAndroidInjector
 import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers
 import io.reactivex.rxjava3.core.Single
 import io.reactivex.rxjava3.schedulers.Schedulers
@@ -67,10 +69,13 @@ import java.io.FileNotFoundException
 import java.io.FileOutputStream
 import java.io.IOException
 import java.util.Locale
+import javax.inject.Inject
 
 typealias ToolbarVisibilityListener = (isVisible: Boolean) -> Unit
 
-class ViewMediaActivity : BaseActivity(), ViewImageFragment.PhotoActionsListener, ViewVideoFragment.VideoActionsListener {
+class ViewMediaActivity : BaseActivity(), HasAndroidInjector, ViewImageFragment.PhotoActionsListener, ViewVideoFragment.VideoActionsListener {
+    @Inject
+    lateinit var androidInjector: DispatchingAndroidInjector<Any>
 
     private val binding by viewBinding(ActivityViewMediaBinding::inflate)
 
@@ -337,6 +342,8 @@ class ViewMediaActivity : BaseActivity(), ViewImageFragment.PhotoActionsListener
         shareFile(file, mimeType)
     }
 
+    override fun androidInjector() = androidInjector
+
     companion object {
         private const val EXTRA_ATTACHMENTS = "attachments"
         private const val EXTRA_ATTACHMENT_INDEX = "index"