Multiple A11y fixes to ReactionButton

[mgamis-msft]

What

• Enhance ReactionButton accessibility by focusing the first emoji button on callout positioning
• Fix focus moving out of ReactionButton flyout when navigating with Tab key
• Screen reader announcing position information for the emoji buttons

Why

https://skype.visualstudio.com/SPOOL/_workitems/edit/4322439
https://skype.visualstudio.com/SPOOL/_workitems/edit/4312689
https://skype.visualstudio.com/SPOOL/_workitems/edit/4322423

How Tested

Tested locally
https://github.com/user-attachments/assets/bda9a74e-ba70-4644-a220-dd980ef34f5b

Process & policy checklist

• I have updated the project documentation to reflect my changes if necessary.
• I have read the CONTRIBUTING documentation.

Is this a breaking change?

• This change causes current functionality to break.

[github-actions]

Storybook 8 URL https://60c7ae6891f0e90039d7cd54-bmdcazolly.chromatic.com/

[github-actions]

@azure/communication-react jest test coverage for stable.

	Lines	Statements	Functions	Branches
Base	29739 / 47381 62.76%	29739 / 47381 62.76%	810 / 1491 54.32%	2394 / 3842 62.31%
Current	29669 / 47420 62.56%	29669 / 47420 62.56%	814 / 1496 54.41%	2436 / 3864 63.04%
Diff	-70 / 39 -0.2%	-70 / 39 -0.2%	4 / 5 0.09%	42 / 22 0.73%

[github-actions]

@azure/communication-react jest test coverage for beta.

	Lines	Statements	Functions	Branches
Base	58580 / 95109 61.59%	58580 / 95109 61.59%	1180 / 2709 43.55%	3417 / 5799 58.92%
Current	58510 / 95186 61.46%	58510 / 95186 61.46%	1184 / 2714 43.62%	3425 / 5805 59%
Diff	-70 / 77 -0.13%	-70 / 77 -0.13%	4 / 5 0.07%	8 / 6 0.08%

[github-actions]

Failed to pass the UI Test. If this PR is for UI change and the error is snapshot mismatch, please add "update_snapshots" label to the PR for updating the snapshot.

[github-actions]

Storybook 8 URL https://60c7ae6891f0e90039d7cd54-mrpyazeqnu.chromatic.com/

[github-actions]

📦 Calling bundle size

Bundle	Base Size (bytes)	Current Size (bytes)	Change	Delta (bytes)
build.bundle.js	6767681	6768435	⚠️ increased	754
580.bundle.js	12407925	12407925	➖ unchanged	0

Total change: +754 B ⚠️

[github-actions]

📦 CallWithChat bundle size

Bundle	Base Size (bytes)	Current Size (bytes)	Change	Delta (bytes)
build.bundle.js	7758336	7759115	⚠️ increased	779
450.bundle.js	4470	4470	➖ unchanged	0
580.bundle.js	12407938	12407938	➖ unchanged	0
727.bundle.js	372564	372564	➖ unchanged	0
82.bundle.js	28177	28155	⬇️ decreased	-22
91.bundle.js	4118	4118	➖ unchanged	0

Total change: +757 B ⚠️

[github-actions]

📦 Chat bundle size

Bundle	Base Size (bytes)	Current Size (bytes)	Change	Delta (bytes)
build.bundle.js	1793916	1793883	⬇️ decreased	-33
398.bundle.js	375829	375829	➖ unchanged	0
450.bundle.js	4454	4454	➖ unchanged	0
82.bundle.js	28161	28139	⬇️ decreased	-22
91.bundle.js	4102	4102	➖ unchanged	0

Total change: -55 B ⬇️

[github-actions]

Storybook 8 URL https://60c7ae6891f0e90039d7cd54-tavkjpszqq.chromatic.com/