fix: allows menu to position correctly in RTL

[geotrev]

Description

Configures RTl override in Floating UI (FUI).

Detail

FUI determines RTL from direction: rtl in the style cascade. This PR sets an override to the platform utility function that now points to theme.rtl.

Checklist

• 👌 design updates will be Garden Designer approved (add the designer as a reviewer)
• 🌐 demo is up-to-date (npm start)
• ⬅️ renders as expected with reversed (RTL) direction
• 🤘 renders as expected with Bedrock CSS (?bedrock)
• 💂‍♂️ includes new unit tests. Maintain existing coverage (always >= 96%)
• ♿ tested for WCAG 2.1 AA accessibility compliance
• 📝 tested in Chrome, Firefox, Safari, and Edge

[coveralls]

coverage: 96.194%. remained the same
when pulling 1b374f1 on george/menu-rtl
into 1f19180 on main.

[jzempel]

We don't want the direction approach as the current Button (and legacy Menu) don't use that. Instead, the Garden-to-Popper placement logic needs refinement for RTL.

[jzempel]

Nice. Please update this PR's description accordingly.