MM-52282 Remove ExperimentalSettings.PatchPluginsReactDOM (#23172)

* MM-52282 Remove ExperimentalSettings.PatchPluginsReactDOM

* Fix missing file from last commit

* Fix test usage of plugin.NewEnvironment

webapp/platform/types/src/config.ts

@@ -729,7 +729,6 @@ export type ExperimentalSettings = {
     EnableSharedChannels: boolean;
     EnableRemoteClusterService: boolean;
     EnableAppBar: boolean;
-    PatchPluginsReactDOM: boolean;
     DisableRefetchingOnBrowserFocus: boolean;
     DelayChannelAutocomplete: boolean;
 };