Google OAuth support for Gemini Plan Packages in Advanced Copy/Paste

### Description of the new feature / enhancement

Support Plan packages from Google Gemini as well as the API Keys.

### Scenario when this would be used?

When you have a Google AI Plan that authenticates via OAuth such as AI Pro, or AI Ultra.

### Supporting information

https://ai.google.dev/gemini-api/docs/oauth

Start by reviewing Advanced Copy/Paste's existing API-key authentication and the linked Google Gemini OAuth documentation. Done means Google AI Plan packages such as AI Pro and AI Ultra can authenticate through OAuth in addition to API keys.

Written by the indexing model from the issue text.