[MM-51201/MM-60406/MM-60404] CrossTeam Search posts and files (#28478)

* poc - wip

* add search files across teams

* eslint

* fix existing tests

* fix webapp style

* fix test

* add api doc

* change initial state in test

* add tests on API

* add tests on file info layer

* fix file search tags

* add rhs reducer test

* reset team selected when the RHS is suppressed

* change css to reflect UI

* fix style

* fix doc wording

* make getSearchTeam return currentTeamId when value is not set

* await is unnecessary

* revert boolean check and add test

* add comment to getSearchTeam to let dev knows it defaults to currentTeam

* remove redundant team check

* simplfy test

* fix style check

---------

Co-authored-by: Caleb Roseland <caleb@calebroseland.com>
Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/store/sqlstore/file_info_store.go

@@ -519,7 +519,6 @@ func (fs SqlFileInfoStore) Search(rctx request.CTX, paramsList []*model.SearchPa
 		From("FileInfo").
 		LeftJoin("Channels as C ON C.Id=FileInfo.ChannelId").
 		LeftJoin("ChannelMembers as CM ON C.Id=CM.ChannelId").
-		Where(sq.Or{sq.Eq{"C.TeamId": teamId}, sq.Eq{"C.TeamId": ""}}).
 		Where(sq.Eq{"FileInfo.DeleteAt": 0}).
 		Where(sq.Or{
 			sq.Eq{"FileInfo.CreatorId": model.BookmarkFileOwner},
@@ -528,6 +527,10 @@ func (fs SqlFileInfoStore) Search(rctx request.CTX, paramsList []*model.SearchPa
 		OrderBy("FileInfo.CreateAt DESC").
 		Limit(100)
 
+	if teamId != "" {
+		query = query.Where(sq.Or{sq.Eq{"C.TeamId": teamId}, sq.Eq{"C.TeamId": ""}})
+	}
+
 	for _, params := range paramsList {
 		params.Terms = removeNonAlphaNumericUnquotedTerms(params.Terms, " ")