Breakout rooms banner fix for react 17 and lower

[mgamis-msft]

What

Fix BreakoutRoomsBanner component to return null instead of undefined when there is no breakout room state because React versions lower that 18 will throw an error if components return undefined according to this discussion post reactwg/react-18#75

Why

Identity pass found this error on mobile form factor when joining a group call with the Call composite

How Tested

Tested local sample and used React 17 to confirm that no error is thrown.

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]

Calling bundle size is not changed.

• Current size: 8139366
• Base size: 8139366
• Diff size: 0

[github-actions]

CallWithChat bundle size is not changed.

• Current size: 8139379
• Base size: 8139379
• Diff size: 0

[github-actions]

Chat bundle size is increased❗.

• Current size: 1757581
• Base size: 1757580
• Diff size: 1

[github-actions]

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

[github-actions]

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

	Lines	Statements	Functions	Branches
Base	26860 / 43236 62.12%	26860 / 43236 62.12%	733 / 1342 54.61%	2136 / 3420 62.45%
Current	26855 / 43236 62.11%	26855 / 43236 62.11%	733 / 1342 54.61%	2149 / 3430 62.65%
Diff	-5 / 0 -0.01%	-5 / 0 -0.01%	0 / 0 0%	13 / 10 0.2%

[github-actions]

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

	Lines	Statements	Functions	Branches
Base	53848 / 88045 61.15%	53848 / 88045 61.15%	1100 / 2488 44.21%	3222 / 5331 60.43%
Current	53838 / 88045 61.14%	53838 / 88045 61.14%	1100 / 2488 44.21%	3222 / 5334 60.4%
Diff	-10 / 0 -0.01%	-10 / 0 -0.01%	0 / 0 0%	0 / 3 -0.03%

[mgamis-msft]

We should guard our components from returning undefined. However, there is only a draft PR to enforce it for eslint-plugin-react jsx-eslint/eslint-plugin-react#3750

[github-actions]

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

[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]

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]

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.