Thread composer UI (#6050)

* Basic adding of posts

* Switch active post on focus

* Conditionally show plus button

* Insert posts midthread

* Track active/inactive post

* Delete posts in a thread

* Focus after deletion

* Tweak empty post detection

* Mix height for active only

* Move toolbar with post on web

* Fix footer positioning

* Post All button

* Fix reply to positioning

* Improve memoization

* Improve memoization for clearVideo

* Remove unnecessary argument

* Add some manual memoization to fix re-renders

* Scroll to bottom on add new

* Fix opacity on Android

* Add backdrop

* Fix videos

* Check alt for video too

* Clear pending publish on error

* Fork alt message by type

* Separate placeholder for next posts

* Limit hitslop to avoid clashes

package.json

@@ -68,7 +68,7 @@
     "@fortawesome/free-regular-svg-icons": "^6.1.1",
     "@fortawesome/free-solid-svg-icons": "^6.1.1",
     "@fortawesome/react-native-fontawesome": "^0.3.2",
-    "@haileyok/bluesky-video": "0.2.3",
+    "@haileyok/bluesky-video": "0.2.4",
     "@ipld/dag-cbor": "^9.2.0",
     "@lingui/react": "^4.5.0",
     "@mattermost/react-native-paste-input": "^0.7.1",