Fix #20721: Guard against null site, account, site.email and account.avatarUrl values

[maxme]

Fixes #20721

Guard against null site, account, site.email and account.avatarUrl values

Regression Notes

1. Potential unintended areas of impact

   • This is very limited change
   • Returns an empty string as the avatar URL in case of an unexpected input, this will result in showing the avatar default (fallback image).

2. What I did to test those areas of impact (or what existing automated tests I relied on)

   • No test

3. What automated tests I added (or what prevented me from doing so)

   • No automated tests

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PR Submission Checklist:

• [x] I have completed the Regression Notes.
• [x] I have considered adding accessibility improvements for my changes.
• [x] I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

---

Testing Checklist (strike-out the not-applying and unnecessary ones):

~- [ ] WordPress.com sites and self-hosted Jetpack sites.~ ~- [ ] Portrait and landscape orientations.~ ~- [ ] Light and dark modes.~ ~- [ ] Fonts: Larger, smaller and bold text.~ ~- [ ] High contrast.~ ~- [ ] Talkback.~ ~- [ ] Languages with large words or with letters/accents not frequently used in English.~ ~- [ ] Right-to-left languages. (Even if translation isn’t complete, formatting should still respect the right-to-left layout)~ ~- [ ] Large and small screen sizes. (Tablet and smaller phones)~ ~- [ ] Multi-tasking: Split screen and Pop-up view. (Android 10 or higher)~

[dangermattic]

	1 Warning
:warning:	This PR is assigned to the milestone 24.8. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

Generated by :no_entry_sign: Danger

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[wpmobilebot]

📲 You can test the changes from this Pull Request in Jetpack by scanning the QR code below to install the corresponding build.

	App Name	Jetpack
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20724-4bbea9c
	Commit	4bbea9c44aef6983e23c3729e0eda72c66865290
	Direct Download	jetpack-prototype-build-pr20724-4bbea9c.apk

Note: Google Login is not supported on these builds.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Flavor	Jalapeno
	Build Type	Debug
	Version	pr20724-4bbea9c
	Commit	4bbea9c44aef6983e23c3729e0eda72c66865290
	Direct Download	wordpress-prototype-build-pr20724-4bbea9c.apk

Note: Google Login is not supported on these builds.