chore(theming): clearer settings app config regex

Better match intent; no practical operational change today.

Signed-off-by: Josh <josh.t.richards@gmail.com>

Author: joshtrichards

apps/theming/lib/Settings/Admin.php

@@ -107,7 +107,7 @@ public function getName(): ?string {
 
 	public function getAuthorizedAppConfig(): array {
 		return [
-			Application::APP_ID => '/.*/',
+			Application::APP_ID => '/^.*$/',
 		];
 	}
 }