fix(fuselage): ButtonGroup margin spacing in RTL mode

[Anshumancanrock]

Fixed ButtonGroup RTL spacing by adding explicit [dir='rtl'] overrides for first and last child margins. The postcss-logical plugin was converting CSS logical properties to physical properties (margin-left/right) without generating proper RTL fallback rules, causing incorrect spacing in RTL layouts.

Closes #1851

Steps to test or reproduce

1. Login to Rocket.Chat
2. Change language to Arabic
3. Navigate to Account → Preferences
4. Scroll to the bottom and observe the Cancel and Save Changes buttons
5. Verify proper spacing between buttons
6. Switch back to English and verify LTR layout still looks good

Before fix:

After fix:

• Bug Fixes

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🦋 Changeset detected

Latest commit: 843bd49

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@rocket.chat/fuselage	Patch

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[juliajforesti]

hey @Anshumancanrock !
thanks for pointing that out for us! we followed a different approach in the reffered PR to have a more wide improvement.
but we appreciate your contribution!