Bug/fix credentials role ignoring update secrets

[ecchong]

What does this PR do?

Fix problem with credentials role always changing the secret even when 'update_secrets: false' is set. When evaluating the 'update_secrets' parameter, 'default' is forcing it to true when 'update_secrets' is set to false.

The normal behavior should not change the secret when user is setting 'update_secrets: false' and providing all required input matching the credential type.

The secret should only be changed when 'update_secrets' is set to true or not defined, and the credential inputs (except the secret value) are different from existing credential.

How should this be tested?

Explicitly setting controller_credentials variable like following with update_secrets as false

controller_credentials:
- name: "test-ssh-key"
  description: Testing password overwritten
  organization: "Test Org"
  credential_type: Machine
  update_secrets: true
  inputs:
    username: root
    ssh_key_data: |
      -----BEGIN OPENSSH PRIVATE KEY-----
      b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAABlwAAAAdzc2gtcn
      NhAAAAAwEAAQAAAYEAsOeWLkvhr58gJWd7n9oNBFCqVduQprjD1KhGpBLq2iPsYlOn48p4
      NCW/oYJ77HyubpzKUfwL0c8R8EnQOZVgudGonuzaINyfyK7JXbT4PAztcAxwGInK4TJPcz
      gRnAlrTLkAcCRHB9VKENmaD3RFnFRTy6lH9JcPoeYRzFpj4dziAKbHn8GdWThCp9GqxNp3
      A6zcsRpJC+sGkAAAARZWNob25nQGVjaG9uZy1tYWMBAg==
      -----END OPENSSH PRIVATE KEY-----
    become_method: ""
    become_username: ""

This always change the secret. Debugging shows the call to credential.py with update_secrets variable always set to true

Is there a relevant Issue open for this?

No

Other Relevant info, PRs, etc

[djdanielsson]

LGTM

[sean-m-sullivan]

LGTM, figuring out the other issues