Bump svg sanitization library

[darylldoyle]

Description of the Change

Updated the enshrined/svg-sanitize package from version ^0.21.0 to ^0.22.0 in composer.json to use the latest release.

This updated resolves an issue where attribute name case inconsistencies (e.g., xlink:Href instead of xlink:href) in XML processing could cause namespace lookups and sanitisation to fail. Attribute names in both namespaced and non-namespaced contexts are now normalised to their expected lowercase form before processing. This ensures consistent sanitisation of xlink:href and other targeted attributes regardless of their original case.

Changelog Entry

• Security - Updated the sanitisation library to fix an issue with case-insensitive attributes slipping through the sanitiser.

Credits

@darylldoyle

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• All new and existing tests pass.

[github-actions]

@darylldoyle thanks for the PR! Could you please fill out the PR template with description, changelog, and credits information so that we can properly review and merge this?

[dkotter]

Tested with an svg that had an anchor tag with the attribute xlink:hReF. Before this PR, that attribute was not being sanitized. After pulling this PR and running composer install, the attribute does get sanitized properly