Fix compilation warnings for MapBuffer

Summary:
We have two warnings on MapBuffer which I'd like to resolve as they show up on console every time.
1. We're using a deprecated method receiveCommand, which is actually legit but was missing a propagation of the warning. I'm adding it.
2. We had a null check that that was always not null. That is enforced by the Kotlin type system. I've checked the code and
we're actually always returning non-nulls there or raising exceptions instead.

Changelog:
[Internal] [Changed] - Fix compilation warnings for MapBuffer

Reviewed By: javache

Differential Revision: D41522129

fbshipit-source-id: c2dbb660f95a2ff7dac6e4fcdf476e4058cf730e

ReactAndroid/src/main/java/com/facebook/react/views/view/ReactMapBufferPropSetter.kt

@@ -255,11 +255,9 @@ object ReactMapBufferPropSetter {
     for (entry in mapBuffer) {
       val map = JavaOnlyMap()
       val action = entry.mapBufferValue
-      if (action != null) {
-        map.putString("name", action.getString(ACCESSIBILITY_ACTION_NAME))
-        if (action.contains(ACCESSIBILITY_ACTION_LABEL)) {
-          map.putString("label", action.getString(ACCESSIBILITY_ACTION_LABEL))
-        }
+      map.putString("name", action.getString(ACCESSIBILITY_ACTION_NAME))
+      if (action.contains(ACCESSIBILITY_ACTION_LABEL)) {
+        map.putString("label", action.getString(ACCESSIBILITY_ACTION_LABEL))
       }
       actions.add(map)
     }

ReactAndroid/src/main/java/com/facebook/react/views/view/ReactViewManagerWrapper.kt

@@ -64,7 +64,7 @@ interface ReactViewManagerWrapper {
     }
 
     override fun receiveCommand(root: View, commandId: Int, args: ReadableArray?) {
-      viewManager.receiveCommand(root, commandId, args)
+      @Suppress("DEPRECATION") viewManager.receiveCommand(root, commandId, args)
     }
 
     override fun setPadding(view: View, left: Int, top: Int, right: Int, bottom: Int) {