[Nullsafe fix nullsafe FIXMEs for BaseJavaModule.java and mark nullsafe

Summary:
Gone trough all the FIXMEs added in the previous diff by the nullsafe tool, marked the class as nullsafe and ensured no remaining violations.
Changelog: [Android][Fixed] Made BaseJavaModule.java nullsafe

Reviewed By: alanleedev

Differential Revision: D72384078

fbshipit-source-id: aba0f261f3b3e77133ff2a148bf4903c73c54691

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/animated/NativeAnimatedModule.kt

@@ -442,7 +442,7 @@ public class NativeAnimatedModule(reactContext: ReactApplicationContext?) :
       return
     }
 
-    val reactApplicationContext = reactApplicationContext
+    val reactApplicationContext = reactApplicationContextIfActiveOrWarn
     if (reactApplicationContext != null) {
       val uiManager = UIManagerHelper.getUIManager(reactApplicationContext, uiManagerType)
       if (uiManager != null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/bridge/BaseJavaModule.java

@@ -12,6 +12,7 @@ import static com.facebook.infer.annotation.ThreadConfined.ANY;
 import androidx.annotation.Nullable;
 import com.facebook.common.logging.FLog;
 import com.facebook.infer.annotation.Assertions;
+import com.facebook.infer.annotation.Nullsafe;
 import com.facebook.infer.annotation.ThreadConfined;
 import com.facebook.proguard.annotations.DoNotStrip;
 import com.facebook.react.common.ReactConstants;
@@ -48,6 +49,7 @@ import java.util.Map;
  * <p>Please note that it is not allowed to have multiple methods annotated with {@link ReactMethod}
  * with the same name.
  */
+@Nullsafe(Nullsafe.Mode.LOCAL)
 @StableReactNativeAPI
 public abstract class BaseJavaModule implements NativeModule {
   // taken from Libraries/Utilities/MessageQueue.js
@@ -118,8 +120,7 @@ public abstract class BaseJavaModule implements NativeModule {
    */
   @ThreadConfined(ANY)
   protected @Nullable final ReactApplicationContext getReactApplicationContextIfActiveOrWarn() {
-    // NULLSAFE_FIXME[Nullable Dereference]
-    if (mReactApplicationContext.hasActiveReactInstance()) {
+    if (mReactApplicationContext != null && mReactApplicationContext.hasActiveReactInstance()) {
       return mReactApplicationContext;
     }