[MM-62427] Add message attachments validation (#30180)

* Add message attachments validation

* Add props validation

* Validate slack attachment fields

* Update tests and library usage

* Improve interactive dialog error for length checks

* Allow predefined colors for slack attachments

* Fix TestPostAction

* Use const for data source

* Add tests

* Cleanup unused props

* Add happy path tests

* lint fixes

* Add validation for PostActionOptions

server/public/pluginapi/experimental/panel/settings/bool_setting.go

@@ -75,6 +75,7 @@ func (s *boolSetting) GetSlackAttachments(userID, settingHandler string, disable
 		currentValueMessage = fmt.Sprintf("Current value: %s", currentTextValue)
 
 		actionTrue := model.PostAction{
+			Type: model.PostActionTypeButton,
 			Name: "Yes",
 			Integration: &model.PostActionIntegration{
 				URL: settingHandler,
@@ -86,6 +87,7 @@ func (s *boolSetting) GetSlackAttachments(userID, settingHandler string, disable
 		}
 
 		actionFalse := model.PostAction{
+			Type: model.PostActionTypeButton,
 			Name: "No",
 			Integration: &model.PostActionIntegration{
 				URL: settingHandler,

server/public/pluginapi/experimental/panel/settings/option_setting.go

@@ -62,6 +62,7 @@ func (s *optionSetting) GetSlackAttachments(userID, settingHandler string, disab
 		currentValueMessage = fmt.Sprintf("Current value: %s", currentTextValue)
 
 		actionOptions := model.PostAction{
+			Type: model.PostActionTypeSelect,
 			Name: "Select an option:",
 			Integration: &model.PostActionIntegration{
 				URL: settingHandler + "?" + s.id + "=true",
@@ -69,7 +70,6 @@ func (s *optionSetting) GetSlackAttachments(userID, settingHandler string, disab
 					ContextIDKey: s.id,
 				},
 			},
-			Type:    "select",
 			Options: stringsToOptions(s.options),
 		}