Refactor React Server entrypoint to not depend on the client one (#27940)

This refactors the Server Components entrypoint for the `react` package
(ReactServer.js) so that it doesn't depend on the client entrypoint
(React.js). I also renamed React.js to ReactClient.js to make the
separation clearer.

This structure will make it easier to add client-only and server-only
features.

DiffTrain build for commit f16344e.

Author: acdlite

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react-test-renderer/cjs/ReactTestRenderer-dev.js

@@ -25540,7 +25540,7 @@ if (__DEV__) {
       return root;
     }
 
-    var ReactVersion = "18.3.0-canary-5d1b15a4f-20240116";
+    var ReactVersion = "18.3.0-canary-f16344ea6-20240116";
 
     // Might add PROFILE later.
 

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react-test-renderer/cjs/ReactTestRenderer-prod.js

@@ -9122,7 +9122,7 @@ var devToolsConfig$jscomp$inline_1037 = {
     throw Error("TestRenderer does not support findFiberByHostInstance()");
   },
   bundleType: 0,
-  version: "18.3.0-canary-5d1b15a4f-20240116",
+  version: "18.3.0-canary-f16344ea6-20240116",
   rendererPackageName: "react-test-renderer"
 };
 var internals$jscomp$inline_1230 = {
@@ -9153,7 +9153,7 @@ var internals$jscomp$inline_1230 = {
   scheduleRoot: null,
   setRefreshHandler: null,
   getCurrentFiber: null,
-  reconcilerVersion: "18.3.0-canary-5d1b15a4f-20240116"
+  reconcilerVersion: "18.3.0-canary-f16344ea6-20240116"
 };
 if ("undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__) {
   var hook$jscomp$inline_1231 = __REACT_DEVTOOLS_GLOBAL_HOOK__;

compiled-rn/facebook-fbsource/xplat/js/RKJSModules/vendor/react-test-renderer/cjs/ReactTestRenderer-profiling.js

@@ -9550,7 +9550,7 @@ var devToolsConfig$jscomp$inline_1079 = {
     throw Error("TestRenderer does not support findFiberByHostInstance()");
   },
   bundleType: 0,
-  version: "18.3.0-canary-5d1b15a4f-20240116",
+  version: "18.3.0-canary-f16344ea6-20240116",
   rendererPackageName: "react-test-renderer"
 };
 var internals$jscomp$inline_1271 = {
@@ -9581,7 +9581,7 @@ var internals$jscomp$inline_1271 = {
   scheduleRoot: null,
   setRefreshHandler: null,
   getCurrentFiber: null,
-  reconcilerVersion: "18.3.0-canary-5d1b15a4f-20240116"
+  reconcilerVersion: "18.3.0-canary-f16344ea6-20240116"
 };
 if ("undefined" !== typeof __REACT_DEVTOOLS_GLOBAL_HOOK__) {
   var hook$jscomp$inline_1272 = __REACT_DEVTOOLS_GLOBAL_HOOK__;