fix: do not overwrite external inputAccessoryView on Fabric (#48339)

Summary:
If 3rd party libs are using `inputAccessoryView` - the current code can easily break it. Whenever props gets changed we call `setDefaultInputAccessoryView` which will simply overwrite the current `inputAccessoryView` (which is highly undesirable).

The same fix on paper was made ~7 years ago: bf36983

## Changelog:

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[IOS] [FIXED] - Fixed problem with accessory view & 3rd party libs

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Pull Request resolved: #48339

Test Plan: Make sure `inputAccessoryView` functionality works as before

Reviewed By: javache

Differential Revision: D67451188

Pulled By: cipolleschi

fbshipit-source-id: bc3fa82ae15f8acedfd0b4e17bdea69cbd8c8a8d

packages/react-native/React/Fabric/Mounting/ComponentViews/TextInput/RCTTextInputComponentView.mm

@@ -68,6 +68,8 @@ @implementation RCTTextInputComponentView {
    * later comparison insensitive to them.
    */
   NSDictionary<NSAttributedStringKey, id> *_originalTypingAttributes;
+
+  BOOL _hasInputAccessoryView;
 }
 
 #pragma mark - UIView overrides
@@ -610,10 +612,12 @@ - (void)setDefaultInputAccessoryView
        keyboardType == UIKeyboardTypeDecimalPad || keyboardType == UIKeyboardTypeASCIICapableNumberPad) &&
       (containsKeyType || containsInputAccessoryViewButtonLabel);
 
-  if ((_backedTextInputView.inputAccessoryView != nil) == shouldHaveInputAccessoryView) {
+  if (_hasInputAccessoryView == shouldHaveInputAccessoryView) {
     return;
   }
 
+  _hasInputAccessoryView = shouldHaveInputAccessoryView;
+
   if (shouldHaveInputAccessoryView) {
     NSString *buttonLabel = inputAccessoryViewButtonLabel != nil ? inputAccessoryViewButtonLabel
                                                                  : [self returnKeyTypeToString:returnKeyType];