MM-57326: [Shared Channels] Message priority, acknowledgement and persistent notifications need to be synced (#30736)

server/platform/services/sharedchannel/service.go

@@ -78,6 +78,11 @@ type AppIface interface {
 	OnSharedChannelsAttachmentSyncMsg(fi *model.FileInfo, post *model.Post, rc *model.RemoteCluster) error
 	OnSharedChannelsProfileImageSyncMsg(user *model.User, rc *model.RemoteCluster) error
 	Publish(message *model.WebSocketEvent)
+	SaveAcknowledgementForPostWithModel(c request.CTX, acknowledgement *model.PostAcknowledgement) (*model.PostAcknowledgement, *model.AppError)
+	DeleteAcknowledgementForPostWithModel(c request.CTX, acknowledgement *model.PostAcknowledgement) *model.AppError
+	SaveAcknowledgementsForPost(c request.CTX, postID string, userIDs []string) ([]*model.PostAcknowledgement, *model.AppError)
+	GetAcknowledgementsForPost(postID string) ([]*model.PostAcknowledgement, *model.AppError)
+	PreparePostForClient(c request.CTX, post *model.Post, isNewPost, includeDeleted, includePriority bool) *model.Post
 }
 
 // errNotFound allows checking against Store.ErrNotFound errors without making Store a dependency.