Remove componentNameByReactViewName from public API

Summary:
Changelog: [Internal]

Changes guard for `componentNameByReactViewName.h` to private and removes it from public umbrella.

Comment in its implementation file says

```
  // We need this function only for the transition period;
  // eventually, all names will be unified.
```

which strongly suggests it shouldn't be part of the public API.

Differential Revision: D122570794

Author: j-piasecki

packages/react-native/ReactCommon/react/renderer/componentregistry/React/ComponentRegistry.h

@@ -35,7 +35,6 @@
 #include <react/renderer/componentregistry/ComponentDescriptorProvider.h>
 #include <react/renderer/componentregistry/ComponentDescriptorProviderRegistry.h>
 #include <react/renderer/componentregistry/ComponentDescriptorRegistry.h>
-#include <react/renderer/componentregistry/componentNameByReactViewName.h>
 
 #undef RN_UMBRELLA_CONTEXT
 #pragma pop_macro("RN_UMBRELLA_CONTEXT")

packages/react-native/ReactCommon/react/renderer/componentregistry/componentNameByReactViewName.h

@@ -7,7 +7,7 @@
 
 #pragma once
 
-#include <react/cxxstableapi/UmbrellaGuard.h>
+#include <react/cxxstableapi/PrivateGuard.h>
 
 #include <string>