Fix game speed UI not resetting when game is restarted

_reset_time_scales() has a visibility guard that was originally needed
to prevent resets on session start. After 4e06e30 scoped the call to
only run when all sessions end, the guard is unnecessary and prevents
the speed state from being properly reset.

Fixes #115400.

Author: nanodeath

editor/run/game_view_plugin.cpp

@@ -676,9 +676,6 @@ void GameView::_embed_options_menu_menu_id_pressed(int p_id) {
 }
 
 void GameView::_reset_time_scales() {
-	if (!is_visible_in_tree()) {
-		return;
-	}
 	time_scale_index = DEFAULT_TIME_SCALE_INDEX;
 	debugger->reset_time_scale();
 	_update_speed_buttons();