[MM-34166] Fix Flaky Test TestGenerateSupportPacket (#17207)

* fix flaky tests

* Revert "fix flaky tests"

This reverts commit 255ce27bf618687927017e1947ad12a538cd525f.

* Fix flaky test

* Fix equal

app/server_test.go

@@ -205,7 +205,12 @@ func TestStartServerTLSSuccess(t *testing.T) {
 
 func TestDatabaseTypeAndMattermostVersion(t *testing.T) {
 	sqlDrivernameEnvironment := os.Getenv("MM_SQLSETTINGS_DRIVERNAME")
-	defer os.Setenv("MM_SQLSETTINGS_DRIVERNAME", sqlDrivernameEnvironment)
+
+	if sqlDrivernameEnvironment != "" {
+		defer os.Setenv("MM_SQLSETTINGS_DRIVERNAME", sqlDrivernameEnvironment)
+	} else {
+		defer os.Unsetenv("MM_SQLSETTINGS_DRIVERNAME")
+	}
 
 	os.Setenv("MM_SQLSETTINGS_DRIVERNAME", "postgres")