MM-33913: Fix read-after-write issues with team member (#17173)

During LDAP sync, we would call AddTeamMember which had a read-after-write issue
where we would create a team member but then immediately after that
query the team member.

The same pattern was found in:
AddTeamMember
AddTeamMembers
AddTeamMemberByToken

To fix this, we just return the inserted team member from AddUserToTeam and use that
instead of query GetTeamMember again.

```release-note
NONE
```

https://mattermost.atlassian.net/browse/MM-33913

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

cmd/mattermost/commands/team.go

@@ -243,7 +243,7 @@ func addUserToTeam(a *app.App, team *model.Team, user *model.User, userArg strin
 		CommandPrintErrorln("Can't find user '" + userArg + "'")
 		return
 	}
-	if err := a.JoinUserToTeam(team, user, ""); err != nil {
+	if _, err := a.JoinUserToTeam(team, user, ""); err != nil {
 		CommandPrintErrorln("Unable to add '" + userArg + "' to " + team.Name)
 		return
 	}