Make useConcurrentRoot always true in renderElement

Summary:
Changelog: [Internal]

All apps have migrated to concurrent root (as they're using Fabric), so the `useConcurrentRoot` parameter is no longer needed. This removes `useConcurrentRoot` (and `useFabric`) from `renderElement` in `RendererImplementation` and the profiling variant, hardcoding the underlying call to `true`, and stops passing them from `renderApplication`.

Differential Revision: D101981133

Author: rubennorte

packages/react-native/Libraries/ReactNative/RendererImplementation.js

@@ -57,19 +57,15 @@ let cachedFabricRender;
 export function renderElement({
   element,
   rootTag,
-  useFabric,
-  useConcurrentRoot,
 }: {
   element: React.MixedElement,
   rootTag: number,
-  useFabric: boolean,
-  useConcurrentRoot: boolean,
 }): void {
   if (cachedFabricRender == null) {
     cachedFabricRender = getFabricRenderer().render;
   }
 
-  cachedFabricRender(element, rootTag, null, useConcurrentRoot, {
+  cachedFabricRender(element, rootTag, null, true, {
     onCaughtError,
     onUncaughtError,
     onRecoverableError,

packages/react-native/Libraries/ReactNative/renderApplication.js

@@ -97,8 +97,6 @@ export default function renderApplication<Props extends Object>(
   Renderer.renderElement({
     element: renderable,
     rootTag,
-    useFabric: true,
-    useConcurrentRoot: true,
   });
   performanceLogger.stopTimespan('renderApplication_React_render');
 }