Fixes #64071

# Objective

Fix `Help → Email Us...` on Linux when using an affected version of
`ashpd`.

The `mailto:` URI generated by Zed is valid, but older `ashpd` versions
incorrectly reject URIs that contain a scheme without `://`, causing the
URI to fail before it can be opened.

## Solution

Update the `ashpd` dependency to `0.13.5`, which contains the upstream
fix for URI parsing
([ashpd#385](https://github.com/bilelmoussaoui/ashpd/issues/385),
[ashpd#386](https://github.com/bilelmoussaoui/ashpd/pull/386)).

Also update `Cargo.lock` to ensure the fixed version is used.

## Testing

Verified that `cargo tree -p ashpd` resolves to `ashpd v0.13.5` and that
the project builds successfully.

## Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

## Showcase

Not applicable. This PR does not introduce a visual change or new
user-facing UI.

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Release Notes:

- Fixed Linux `mailto:` URI handling when using `Help → Email Us...`.

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Co-authored-by: Kirill Bulatov <mail4score@gmail.com>