Update flutter_math_fork

[edhom]

Description

This updates flutter_math_fork to the latest version.

Related issues & PRs

n/a

Checklist

• [x] I have made myself familiar with the CaTeX contributing guide.
• [x] I added a PR description.
• [x] I linked all related issues and PRs I could find (no links if there are none).
• [x] If this PR changes anything about the main math_keyboard or example package (also README etc.), I created an entry in CHANGELOG.md (## UPCOMING RELEASE if the change on its own is not worth an update).
• [x] If this PR includes a notable change in the math_keyboard package, I updated the version according to Dart's semantic versioning.
• [x] If there is new functionality in code, I added tests covering all my additions.
• [x] All required checks pass.

[edhom]

@creativecreatorormaybenot Oh I thought we don't add an entry for patches:D The test were failing cause the latest version of flutter_svg is used, which requires flutter 2.5 iirc (see the use of LayerHandle). But the flutter-action workflow used in the checks used an old flutter version. Updating it fixed it:)