Release Notes:

- copilot: Improve robustness of copilot chat provider by splitting
authorisation paths for edit predictions and chat. Note: Existing users
will have to re-authenticate with Copilot

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Co-authored-by: cameron <cameron.studdstreet@gmail.com>
Co-authored-by: zed-zippy[bot] <234243425+zed-zippy[bot]@users.noreply.github.com>