MM-29107: Fix race in LDAP login (#16239)

* MM-29107: Fix race in LDAP login

We remove the goroutine to make things synchronous.

This removes the race and makes things more reliable.
It is already tested by TestLogin in ldap_test.go in -race mode.

https://mattermost.atlassian.net/browse/MM-29107

```release-note
NONE
```

* Address review comments

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

einterfaces/ldap.go

@@ -21,6 +21,6 @@ type LdapInterface interface {
 	GetGroup(groupUID string) (*model.Group, *model.AppError)
 	GetAllGroupsPage(page int, perPage int, opts model.LdapGroupSearchOpts) ([]*model.Group, int, *model.AppError)
 	FirstLoginSync(user *model.User, userAuthService, userAuthData, email string) *model.AppError
-	UpdateProfilePictureIfNecessary(model.User, *model.Session)
+	UpdateProfilePictureIfNecessary(model.User, model.Session)
 	GetADLdapIdFromSAMLId(authData string) string
 }

einterfaces/mocks/LdapInterface.go

@@ -305,6 +305,6 @@ func (_m *LdapInterface) SwitchToLdap(userId string, ldapId string, ldapPassword
 }
 
 // UpdateProfilePictureIfNecessary provides a mock function with given fields: _a0, _a1
-func (_m *LdapInterface) UpdateProfilePictureIfNecessary(_a0 model.User, _a1 *model.Session) {
+func (_m *LdapInterface) UpdateProfilePictureIfNecessary(_a0 model.User, _a1 model.Session) {
 	_m.Called(_a0, _a1)
 }