Remove Default LLM Provider Settings in frontend and Fetch from Backend

[Kaveri-Jeevanantham]

Currently, the default LLM provider settings are set in the Electron app. This approach limits flexibility and prevents dynamic updates from the backend.

Acceptance Criteria:

• Remove default LLM provider settings from Electron.
• Implement API call to fetch default LLM provider settings from the backend during the first login.
• Persist the fetched settings locally for reuse in future logins.
• On subsequent logins, if the current LLM provider fails, reset it to the default provider from the backend.
• Ensure seamless error handling and fallback mechanisms.

[Kaveri-Jeevanantham]

A PR has been created to address this feature request: #8

[Kaveri-Jeevanantham]

Closing the Discussion as the PR has been merged. The feature will be available from v1.9.6