refactor: 💡 update credential-library form for password type (#3060)

* refactor: 💡 update credential-library form for password type

* style: 💄 fix display issue

* test: 💍 add test cases

addons/api/addon/generated/models/credential-library.js

@@ -81,9 +81,10 @@ export default class GeneratedCredentialLibraryModel extends BaseModel {
   })
   credential_type;
 
-  @attr('object-as-array', {
+  @attr('object', {
     for: 'vault-generic',
     description: 'It indicates the credential mapping overrides.',
+    emptyObjectIfMissing: true,
   })
   credential_mapping_overrides;