Fixes #1108

## Summary
The "Setup AI Access" banner was not being hidden when custom providers
were configured. This was because the `isAnyProviderSetup()` function
only checked hardcoded cloud providers and didn't account for custom
providers.

## Changes
Updated `useLanguageModelProviders.ts` to check for configured custom
providers in addition to the hardcoded cloud providers.

## Test plan
- Configure a custom provider without setting up any cloud providers
- Verify that the "Setup AI Access" banner is now hidden

🤖 Generated with [Claude Code](https://claude.com/claude-code)

<!-- This is an auto-generated description by cubic. -->
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## Summary by cubic
Hide the "Setup AI Access" banner when any provider is configured,
including custom providers. Fixes a logic gap where only hardcoded cloud
providers were checked.

- **Bug Fixes**
- Extend isAnyProviderSetup to check custom providers from query data
(by id).
- Banner no longer shows when a custom provider is configured without
cloud providers.

<sup>Written for commit 2ecef7aac52da0b4d43c69fc5d3afb7bafa5706a.
Summary will update automatically on new commits.</sup>

<!-- End of auto-generated description by cubic. -->