Fix Passphrase Credential dialog

Summary: Fixes T10772, not sure why this fails, but reverting the code back to old dialog call works.

Test Plan:

• Try to add a new credential when importing a repository.
• Also created a new credential normally, via Passphrase.
• Also edited a credential.

Reviewers: chad

Reviewed By: chad

Subscribers: Korvin

Maniphest Tasks: T10772

Differential Revision: https://secure.phabricator.com/D15691