## Summary

Fixes #42342

When installing a dev extension with long installation instructions, the
configuration modal would overflow and users couldn't scroll to see the
full content or interact with buttons at the bottom.

## Solution

This PR adds a `ScrollHandle` to the `ConfigureContextServerModal` and
passes it to the `Modal` component, enabling the built-in modal
scrolling capability. This ensures all content remains accessible
regardless of length.

## Changes

- Added `ScrollHandle` import to the ui imports
- Added `scroll_handle: ScrollHandle` field to
`ConfigureContextServerModal` struct
- Initialize `scroll_handle` with `ScrollHandle::new()` when creating
the modal
- Pass the scroll handle to `Modal::new()` instead of `None`

## Testing

- Built the changes locally
- Tested with extensions that have long installation instructions
- Verified scrolling works and all content is accessible
- Confirmed no regression for extensions with short descriptions

Release Notes:

- Fixed scrolling issue in extension configuration modal when
installation instructions overflow the viewport

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Co-authored-by: Finn Evers <finn.evers@outlook.de>