[Fiber] Refactor Commit Phase into Separate Functions for Before Mutation/Mutation/Layout (#31930)

This is doing some general clean up to be able to split the commit root three phases into three separate async steps.

DiffTrain build for [c81312e](c81312e)

Author: sebmarkbage

compiled-rn/VERSION_NATIVE_FB

@@ -1 +1 @@
-19.1.0-native-fb-d8b903f4-20250102
+19.1.0-native-fb-c81312e3-20250102

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react/react-dom/cjs/ReactDOM-dev.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<2b8c1212fd1e8a35748291910efc6e86>>
+ * @generated SignedSource<<02a6ea8d2bfe1b4a480a21cbc05c590b>>
  */
 
 "use strict";
@@ -420,5 +420,5 @@ __DEV__ &&
     exports.useFormStatus = function () {
       return resolveDispatcher().useHostTransitionStatus();
     };
-    exports.version = "19.1.0-native-fb-d8b903f4-20250102";
+    exports.version = "19.1.0-native-fb-c81312e3-20250102";
   })();

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react/react-dom/cjs/ReactDOM-prod.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<cd7e1d3afb6c514b568a5f7a52091f29>>
+ * @generated SignedSource<<355537d2f428007d2a3d9028e140f67d>>
  */
 
 "use strict";
@@ -203,4 +203,4 @@ exports.useFormState = function (action, initialState, permalink) {
 exports.useFormStatus = function () {
   return ReactSharedInternals.H.useHostTransitionStatus();
 };
-exports.version = "19.1.0-native-fb-d8b903f4-20250102";
+exports.version = "19.1.0-native-fb-c81312e3-20250102";

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react/react-dom/cjs/ReactDOM-profiling.js

@@ -7,7 +7,7 @@
  * @noflow
  * @nolint
  * @preventMunge
- * @generated SignedSource<<cd7e1d3afb6c514b568a5f7a52091f29>>
+ * @generated SignedSource<<355537d2f428007d2a3d9028e140f67d>>
  */
 
 "use strict";
@@ -203,4 +203,4 @@ exports.useFormState = function (action, initialState, permalink) {
 exports.useFormStatus = function () {
   return ReactSharedInternals.H.useHostTransitionStatus();
 };
-exports.version = "19.1.0-native-fb-d8b903f4-20250102";
+exports.version = "19.1.0-native-fb-c81312e3-20250102";