Remove isValid from RCTInvalidating

Summary:
We only actually use it on RCTBridge and RCTJavaScriptExecutor, so add it to these interfaces explicitly

React/Base/RCTBatchedBridge.m

@@ -62,6 +62,7 @@ id<RCTJavaScriptExecutor> RCTGetLatestExecutor(void)
 @implementation RCTBatchedBridge
 {
   BOOL _loading;
+  BOOL _valid;
   __weak id<RCTJavaScriptExecutor> _javaScriptExecutor;
   NSMutableArray *_moduleDataByID;
   RCTModuleMap *_modulesByName;
@@ -72,8 +73,6 @@ id<RCTJavaScriptExecutor> RCTGetLatestExecutor(void)
   RCTSparseArray *_scheduledCallbacks;
 }
 
-@synthesize valid = _valid;
-
 - (instancetype)initWithParentBridge:(RCTBridge *)bridge
 {
   RCTAssertMainThread();

React/Base/RCTBridge.h

@@ -145,6 +145,11 @@ RCT_EXTERN NSString *RCTBridgeModuleNameForClass(Class bridgeModuleClass);
  */
 @property (nonatomic, readonly, getter=isLoading) BOOL loading;
 
+/**
+ * Use this to check if the bridge has been invalidated.
+ */
+@property (nonatomic, readonly, getter=isValid) BOOL valid;
+
 /**
  * The block passed in the constructor with pre-initialized modules
  */

React/Base/RCTBridge.m

@@ -244,11 +244,6 @@ RCT_NOT_IMPLEMENTED(-init)
   return _batchedBridge.loading;
 }
 
-- (BOOL)isValid
-{
-  return _batchedBridge.isValid;
-}
-
 - (void)invalidate
 {
   RCTAssertMainThread();
@@ -260,7 +255,7 @@ RCT_NOT_IMPLEMENTED(-init)
 + (void)logMessage:(NSString *)message level:(NSString *)level
 {
   dispatch_async(dispatch_get_main_queue(), ^{
-    if (!RCTGetLatestExecutor().isValid) {
+    if (![RCTGetLatestExecutor() isValid]) {
       return;
     }
 

React/Base/RCTInvalidating.h

@@ -9,13 +9,8 @@
 
 #import <Foundation/Foundation.h>
 
-// TODO (#5906496): This protocol is only used to add method definitions to
-// classes. We should decide if it's actually necessary.
-
 @protocol RCTInvalidating <NSObject>
 
-@property (nonatomic, assign, readonly, getter = isValid) BOOL valid;
-
 - (void)invalidate;
 
 @end

React/Base/RCTJavaScriptExecutor.h

@@ -29,6 +29,11 @@ typedef void (^RCTJavaScriptCallback)(id json, NSError *error);
  */
 - (void)setUp;
 
+/**
+ * Whether the executor has been invalidated
+ */
+@property (nonatomic, readonly, getter=isValid) BOOL valid;
+
 /**
  * Executes given method with arguments on JS thread and calls the given callback
  * with JSValue and JSContext as a result of the JS module call.

React/Base/RCTRootView.m

@@ -292,14 +292,9 @@ RCT_NOT_IMPLEMENTED(-initWithCoder:(NSCoder *)aDecoder)
   [_bridge.uiManager registerRootView:self];
 }
 
-- (BOOL)isValid
-{
-  return self.userInteractionEnabled;
-}
-
 - (void)invalidate
 {
-  if (self.isValid) {
+  if (self.userInteractionEnabled) {
     self.userInteractionEnabled = NO;
     [(RCTRootView *)self.superview contentViewInvalidated];
     [_bridge enqueueJSCall:@"ReactNative.unmountComponentAtNodeAndRemoveContainer"