Fabric: Fixing a crash in RCTParagraphComponentView

Summary:
We don't know why exactly it happens but (seemingly) sometime Paragraph component receives an empty State object. This causes a crash because of unchecked access to an instance variable.
This diff introduces an assert in DEBUG mode and the check for prod.

Why is this happens? Hard to say, probably `layout()` method (which updates `State`) is not being called on ShadowNode. Why? One explanation can be that Yoga skips some subtree during layout because it starts from "visibility: hidden" component. We need to investigate it more and figure out what exactly going on and what should we need to improve besides the check. That's why we have an assertion.

Changelog: [Internal] Fabric-specific internal change.

Reviewed By: sammy-SC

Differential Revision: D20260512

fbshipit-source-id: 4772855f41c6694be2ed6c0a19da40332d2bb8db

React/Fabric/Mounting/ComponentViews/Text/RCTParagraphComponentView.mm

@@ -80,7 +80,13 @@ using namespace facebook::react;
     return;
   }
 
-  SharedTextLayoutManager textLayoutManager = _state->getData().layoutManager;
+  auto textLayoutManager = _state->getData().layoutManager;
+  assert(textLayoutManager && "TextLayoutManager must not be `nullptr`.");
+
+  if (!textLayoutManager) {
+    return;
+  }
+
   RCTTextLayoutManager *nativeTextLayoutManager =
       (__bridge RCTTextLayoutManager *)textLayoutManager->getNativeTextLayoutManager();
 
@@ -113,16 +119,22 @@ using namespace facebook::react;
     return _eventEmitter;
   }
 
-  SharedTextLayoutManager textLayoutManager = _state->getData().layoutManager;
+  auto textLayoutManager = _state->getData().layoutManager;
+
+  assert(textLayoutManager && "TextLayoutManager must not be `nullptr`.");
+
+  if (!textLayoutManager) {
+    return _eventEmitter;
+  }
+
   RCTTextLayoutManager *nativeTextLayoutManager =
       (__bridge RCTTextLayoutManager *)textLayoutManager->getNativeTextLayoutManager();
   CGRect frame = RCTCGRectFromRect(_layoutMetrics.getContentFrame());
 
-  SharedEventEmitter eventEmitter =
-      [nativeTextLayoutManager getEventEmitterWithAttributeString:_state->getData().attributedString
-                                              paragraphAttributes:_paragraphAttributes
-                                                            frame:frame
-                                                          atPoint:point];
+  auto eventEmitter = [nativeTextLayoutManager getEventEmitterWithAttributeString:_state->getData().attributedString
+                                                              paragraphAttributes:_paragraphAttributes
+                                                                            frame:frame
+                                                                          atPoint:point];
 
   if (!eventEmitter) {
     return _eventEmitter;