avoid empty key (#1505)

Author: ildyria

app/Http/Middleware/Checks/IsInstalled.php

@@ -22,6 +22,7 @@ public function assert(): bool
 		try {
 			return
 				config('app.key') !== null &&
+				config('app.key') !== '' &&
 				Schema::hasTable('configs');
 		} catch (QueryException $e) {
 			// Authentication to DB failled.