[MM-58492][MM-58523] Fixed some access control bugs around archived channels by replacing the permission check with HasPermissionToReadChannel (#27409)

* [MM-58492][MM-58523] Fixed some access control bugs around archived channels by replacing the permission check with HasPermissionToReadChannel

* Fix lint, add ChannelId to uploads

* Fix MMCTL tests and remove unnecessary check for the error message that doesn't work anyways

* Include channel map for getting flagged posts

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/authorization.go

@@ -371,6 +371,14 @@ func (a *App) SessionHasPermissionToManageBot(rctx request.CTX, session model.Se
 	return nil
 }
 
+func (a *App) SessionHasPermissionToReadChannel(c request.CTX, session model.Session, channel *model.Channel) bool {
+	if session.IsUnrestricted() {
+		return true
+	}
+
+	return a.HasPermissionToReadChannel(c, session.UserId, channel)
+}
+
 func (a *App) HasPermissionToReadChannel(c request.CTX, userID string, channel *model.Channel) bool {
 	if !*a.Config().TeamSettings.ExperimentalViewArchivedChannels && channel.DeleteAt != 0 {
 		return false