[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>

webapp/platform/client/src/client4.ts

@@ -2473,8 +2473,13 @@ export default class Client4 {
     searchFilesWithParams = (teamId: string, params: any) => {
         this.trackEvent('api', 'api_files_search', {team_id: teamId});
 
+        let route = `${this.getFilesRoute()}/search`;
+        if (teamId) {
+            route = `${this.getTeamRoute(teamId)}/files/search`;
+        }
+
         return this.doFetch<FileSearchResults>(
-            `${this.getTeamRoute(teamId)}/files/search`,
+            route,
             {method: 'post', body: JSON.stringify(params)},
         );
     };