Make boot splash background color always configurable

This also means that you can keep the default Godot splash and
set your own custom background color.

Fixes #22076.

main/main.cpp

@@ -1096,30 +1096,24 @@ Error Main::setup2(Thread::ID p_main_tid_override) {
 				ERR_PRINTS("Non-existing or invalid boot splash at: " + boot_logo_path + ". Loading default splash.");
 		}
 
+		Color boot_bg_color = GLOBAL_DEF("application/boot_splash/bg_color", boot_splash_bg_color);
 		if (boot_logo.is_valid()) {
 			OS::get_singleton()->_msec_splash = OS::get_singleton()->get_ticks_msec();
-			Color boot_bg = GLOBAL_DEF("application/boot_splash/bg_color", clear);
-			VisualServer::get_singleton()->set_boot_image(boot_logo, boot_bg, boot_logo_scale);
-#ifndef TOOLS_ENABLED
-//no tools, so free the boot logo (no longer needed)
-//ProjectSettings::get_singleton()->set("application/boot_logo",Image());
-#endif
+			VisualServer::get_singleton()->set_boot_image(boot_logo, boot_bg_color, boot_logo_scale);
 
 		} else {
 #ifndef NO_DEFAULT_BOOT_LOGO
-
 			MAIN_PRINT("Main: Create bootsplash");
 #if defined(TOOLS_ENABLED) && !defined(NO_EDITOR_SPLASH)
-
 			Ref<Image> splash = (editor || project_manager) ? memnew(Image(boot_splash_editor_png)) : memnew(Image(boot_splash_png));
 #else
 			Ref<Image> splash = memnew(Image(boot_splash_png));
 #endif
 
 			MAIN_PRINT("Main: ClearColor");
-			VisualServer::get_singleton()->set_default_clear_color(boot_splash_bg_color);
+			VisualServer::get_singleton()->set_default_clear_color(boot_bg_color);
 			MAIN_PRINT("Main: Image");
-			VisualServer::get_singleton()->set_boot_image(splash, boot_splash_bg_color, false);
+			VisualServer::get_singleton()->set_boot_image(splash, boot_bg_color, false);
 #endif
 		}