MM-52282 Remove ExperimentalSettings.PatchPluginsReactDOM (#23172)

* MM-52282 Remove ExperimentalSettings.PatchPluginsReactDOM

* Fix missing file from last commit

* Fix test usage of plugin.NewEnvironment

server/model/config.go

@@ -971,7 +971,6 @@ type ExperimentalSettings struct {
 	EnableSharedChannels            *bool   `access:"experimental_features"`
 	EnableRemoteClusterService      *bool   `access:"experimental_features"`
 	EnableAppBar                    *bool   `access:"experimental_features"`
-	PatchPluginsReactDOM            *bool   `access:"experimental_features"`
 	DisableRefetchingOnBrowserFocus *bool   `access:"experimental_features"`
 	DelayChannelAutocomplete        *bool   `access:"experimental_features"`
 }
@@ -1009,10 +1008,6 @@ func (s *ExperimentalSettings) SetDefaults() {
 		s.EnableAppBar = NewBool(false)
 	}
 
-	if s.PatchPluginsReactDOM == nil {
-		s.PatchPluginsReactDOM = NewBool(false)
-	}
-
 	if s.DisableRefetchingOnBrowserFocus == nil {
 		s.DisableRefetchingOnBrowserFocus = NewBool(false)
 	}