[MM-13721] Fix the etag function GetEtagForProfilesNotInTeam (#10360)

* Initial solution for Draft PR

* Reformat tabs to spaces for readability

* Remove my comments and debugging lines for Core Commiter to see changes
more easily

* Remove all comments and show only code changes

* Match indentation spacing of new query to old query to make diff reading
easier for core committer

* Remove everything except what want to show core commiter

* Restrucure query and resulting etag value.
get number of users not in team from SELECT subquery.
etag return values is now of the form
<model.CurrenVersion>.<UpdateAt>.<number_profiles_not_int_team>

* Remove skipped test for solution to https://mattermost.atlassian.net/browse/MM-13721.
Remove comment for failing description of test
store u4 with prepended "u4".  Similar to u1, u2, u3.  This is easier
for debugging when looking in the database
Added skipped test:
  check that etag does not change when a user, not in team 1, is added
  to different team.  UpdateAt will change, but users in the set does
  not

* Remove skipped test for solution to https://mattermost.atlassian.net/browse/MM-13721.
Remove comment for failing description of test
store u4 with prepended "u4".  Similar to u1, u2, u3.  This is easier
for debugging when looking in the database
Added skipped test:
  check that etag does not change when a user, not in team 1, is added
  to different team.  UpdateAt will change, but users in the set does
  not

* remove commented out tests

* Restructure and simplify the SQL query for GetEtagForProfilesNotInTeam.
- Build the query to get all profiles not in a specified team
- select latest UpdateAt Value by getting Max value from UpdateAt field.
- select Number of profiles not in Team from count of the returned Ids

The previous query required building a complex query with multiple
joins and repeated code in a select subquery, and derived table

* Format SQL styling indentation, spaces around equal signs, and new lines

* Add description for skipped test

store/sqlstore/user_store.go

@@ -1348,23 +1348,25 @@ func (us SqlUserStore) GetProfilesNotInTeam(teamId string, offset int, limit int
 
 func (us SqlUserStore) GetEtagForProfilesNotInTeam(teamId string) store.StoreChannel {
 	return store.Do(func(result *store.StoreResult) {
-		updateAt, err := us.GetReplica().SelectInt(`
-            SELECT
-                u.UpdateAt
-            FROM Users u
-            LEFT JOIN TeamMembers tm
-                ON tm.UserId = u.Id
-                AND tm.TeamId = :TeamId
-                AND tm.DeleteAt = 0
-            WHERE tm.UserId IS NULL
-            ORDER BY u.UpdateAt DESC
-            LIMIT 1
-            `, map[string]interface{}{"TeamId": teamId})
 
+		var querystr string
+		querystr = `
+			SELECT 
+				CONCAT(MAX(UpdateAt), '.', COUNT(Id)) as etag
+			FROM 
+				Users as u
+			LEFT JOIN TeamMembers tm 
+				ON tm.UserId = u.Id 
+				AND tm.TeamId = :TeamId 
+				AND tm.DeleteAt = 0
+			WHERE 
+				tm.UserId IS NULL
+		`
+		etag, err := us.GetReplica().SelectStr(querystr, map[string]interface{}{"TeamId": teamId})
 		if err != nil {
 			result.Data = fmt.Sprintf("%v.%v", model.CurrentVersion, model.GetMillis())
 		} else {
-			result.Data = fmt.Sprintf("%v.%v", model.CurrentVersion, updateAt)
+			result.Data = fmt.Sprintf("%v.%v", model.CurrentVersion, etag)
 		}
 	})
 }