fix: prevent model selection failures when API requests fail (fixes #3813, #3874)

[indiesewell]

fix: prevent model selection failures when API requests fail (fixes #3813, fixes #3874)

This PR addresses issues #3813 and #3874 where users were unable to select models in the settings interface when certain provider APIs failed.

Changes:

• Replace Promise.all with Promise.allSettled in webviewMessageHandler.ts to handle provider API failures gracefully
• Fix model initialization logic in ModelPicker component to ensure proper default selection
• Ensure models can be selected even when some provider APIs fail

Technical details:
The previous implementation used Promise.all which would fail entirely if any single provider API request failed. By switching to Promise.allSettled, we now properly handle partial failures and allow users to select from available models even when some providers are unreachable or return errors. Additionally, the initialization logic in ModelPicker has been fixed to properly handle the default model selection.

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Important

Switch to Promise.allSettled for API requests and fix default model selection in ModelPicker to handle failures gracefully.

• Behavior:
  • Replace Promise.all with Promise.allSettled in webviewMessageHandler.ts to handle API failures gracefully.
  • Fix default model selection logic in ModelPicker to ensure proper initialization.
• Technical Details:
  • Promise.allSettled allows handling of partial failures, enabling model selection even if some APIs fail.
  • Initialization logic in ModelPicker ensures default model is selected if no valid model is chosen.

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