Use request.CTX instead of *request.Context (#24877)

* Use request.CTX instead of *request.Context

* Fix tests

server/channels/app/slashcommands/command_mute.go

@@ -37,7 +37,7 @@ func (*MuteProvider) GetCommand(a *app.App, T i18n.TranslateFunc) *model.Command
 	}
 }
 
-func (*MuteProvider) DoCommand(a *app.App, c *request.Context, args *model.CommandArgs, message string) *model.CommandResponse {
+func (*MuteProvider) DoCommand(a *app.App, c request.CTX, args *model.CommandArgs, message string) *model.CommandResponse {
 	var channel *model.Channel
 	var noChannelErr *model.AppError