fix: remove duplicate normalizePolicyKey method in SignatureTextPolicy

Author: vitormattos

lib/Service/Policy/Provider/SignatureText/SignatureTextPolicy.php

@@ -63,12 +63,3 @@ private function normalizePolicyKey(string|\BackedEnum $policyKey): string {
 		return $policyKey;
 	}
 }
-
-	private function normalizePolicyKey(string|\BackedEnum $policyKey): string {
-		if ($policyKey instanceof \BackedEnum) {
-			return (string)$policyKey->value;
-		}
-
-		return $policyKey;
-	}
-}