chore: Only show Whats new if there is a beamer app id

[usame-algan]

What it solves

Relates to #3413

Resolves #3515 (comment)

How this PR fixes it

If no Beamer app id exists, the "Whats New" Button stays hidden and Beamer is not included.

How to test it

1. Open the Safe app on production without a beamer app id in .env
2. Observe that there is no "Whats new" Button in the sidebar
3. Accept all cookies
4. Observe that the console shows a Beamer app id missing warning

[github-actions]

CLA Assistant Lite All Contributors have signed the CLA.

[github-actions]

ESLint Summary View Full Report

Annotations are provided inline on the Files Changed tab. You can also see all annotations that were generated on the annotations page.

Type	Occurrences	Fixable
Errors	0	0
Warnings	0	0
Ignored	0	N/A

• Result: ✅ success
• Annotations: 0 total

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^{Report generated by eslint-plus-action}

[coveralls]

Pull Request Test Coverage Report for Build 1933835969

• 1 of 2 (50.0%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.005%) to 34.867%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/utils/beamer.ts	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/utils/beamer.ts	1	0%

Totals
Change from base Build 1932713526:	0.005%
Covered Lines:	3364
Relevant Lines:	8718

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💛 - Coveralls

[github-actions]

Deployment links

🟠 Rinkeby	⚪ Mainnet	🟣 Polygon	🟡 BSC	⚫ Arbitrum	🟢 Gnosis Chain

[github-actions]

E2E Tests Failed
Check the results here: https://github.com/gnosis/safe-react-e2e-tests/actions/runs/1933873624

Failed tests:

• ❌ Add an existing safe Add an existing safe
• ❌ Read-only transaction creation and review Read-only transaction creation and review
• ❌ Safe Apps List Safe Apps List
• ❌ Safe Balances Safe Balances