make gen_app_builder_settings o+c in google_dialogflow_cx_agent (#14014) (#10036)

[upstream:f78583e18bcf288af383b92cb5ad92d11e496a22]

Signed-off-by: Modular Magician <[email protected]>

Author: modular-magician

google-beta/services/dialogflowcx/resource_dialogflow_cx_agent.go

@@ -233,6 +233,7 @@ A duration in seconds with up to nine fractional digits, ending with 's'. Exampl
 			},
 			"gen_app_builder_settings": {
 				Type:        schema.TypeList,
+				Computed:    true,
 				Optional:    true,
 				Description: `Gen App Builder-related agent-level settings.`,
 				MaxItems:    1,