Enable the errorAssertions govet check for mattermost-server code (#17346)

* Enable the errorAssertions govet check for mattermost-server code

* Removing unnecesary change

* Fixing some tests

* Fixing tests

* Fixing more after merge

* Fixing new offending entries

* Fixing small vet checks

* Fixing new cases detected by govet

* Fixing remote_cluster_test errors

* Fixing assertion

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

api4/team_test.go

@@ -2926,7 +2926,7 @@ func TestInviteGuestsToTeam(t *testing.T) {
 
 	t.Run("invalid data in request body", func(t *testing.T) {
 		res, err := th.SystemAdminClient.DoApiPost(th.SystemAdminClient.GetTeamRoute(th.BasicTeam.Id)+"/invite-guests/email", "bad data")
-		require.Error(t, err)
+		require.NotNil(t, err)
 		require.Equal(t, "api.team.invite_guests_to_channels.invalid_body.app_error", err.Id)
 		require.Equal(t, http.StatusBadRequest, res.StatusCode)
 	})