MetadataService.MetadataPort service = createService();
MetadataService.QuickAction customQuickAction = new MetadataService.QuickAction();
customQuickAction.targetObject = 'Test__c';
customQuickAction.lightningWebComponent = 'CustomLWCComponent';
customQuickAction.actionSubtype = 'ScreenAction';
customQuickAction.label = 'testButton 123';
customQuickAction.fullName = 'Test__c.testButton123';
customQuickAction.description = 'Test 123';
customQuickAction.optionsCreateFeedItem = false;
customQuickAction.type_x = 'LightningWebComponent';
customQuickAction.isProtected = false;
customQuickAction.height = 300;
List<MetadataService.SaveResult> results = service.createMetadata(
new MetadataService.Metadata[] { customQuickAction });
Error - Test__c.testButton123. Required fields are missing: [Component] (REQUIRED_FIELD_MISSING). Fields Component.