[MM-17194] Add search channels for user in case the user doesn't have the list channels permission (#11706)

* [MM-17194] Add search channels for user in case the user doesn't have the list channels permission

* Add tests for the API layer and control the case of a user not being a team member

* Remove unnecessary empty line

store/sqlstore/channel_store.go

@@ -2121,6 +2121,35 @@ func (s SqlChannelStore) SearchInTeam(teamId string, term string, includeDeleted
 	})
 }
 
+func (s SqlChannelStore) SearchForUserInTeam(userId string, teamId string, term string, includeDeleted bool) (*model.ChannelList, *model.AppError) {
+	deleteFilter := "AND c.DeleteAt = 0"
+	if includeDeleted {
+		deleteFilter = ""
+	}
+
+	return s.performSearch(`
+		SELECT
+			Channels.*
+		FROM
+			Channels
+		JOIN
+			PublicChannels c ON (c.Id = Channels.Id)
+        JOIN
+            ChannelMembers cm ON (c.Id = cm.ChannelId)
+		WHERE
+			c.TeamId = :TeamId
+        AND
+            cm.UserId = :UserId
+			`+deleteFilter+`
+			SEARCH_CLAUSE
+		ORDER BY c.DisplayName
+		LIMIT 100
+		`, term, map[string]interface{}{
+		"TeamId": teamId,
+		"UserId": userId,
+	})
+}
+
 func (s SqlChannelStore) SearchAllChannels(term string, opts store.ChannelSearchOpts) (*model.ChannelListWithTeamData, *model.AppError) {
 	query := s.getQueryBuilder().
 		Select("c.*, t.DisplayName AS TeamDisplayName, t.Name AS TeamName, t.UpdateAt as TeamUpdateAt").