User input in some fields of the Directory Connector form is lost when the connection test fails

To reproduce:

1. Create a new Connector, advance to the second tab ("Connector")
2. Make some changes in the fields. Use an invalid combination of inputs so the connection will not work (e.g., bad admin username)
3. Before saving, click on the Test Connection button.
4. The form is reloaded, an error message is displayed. The changes made in Step 2 to the following fields are lost, while the other field values are preserved:
   • Use node referrals (resets to unchecked)
   • Use paged results (resets to unchecked)

Seems related to CWD-1763