Fix UninitializedPropertyAccessException in EditorJetpackSocialViewModel

[RenanLukas]

Fixes #20662

Even though I couldn't reproduce the crash, the root cause seem to be a race condition that makes the method EditorJetpackSocialViewModel#shouldShowJetpackSocial be called before editPostRepository is initialized. As a quick fix to avoid crashing, I'm checking if the variable was initialized before using it.

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To Test:

• Install JP and sign in.
• Select a site that has at least one social network connected.
• Tap "+" FAB in "My Site" screen.
• 🔍 Tap "Blog post" option: the app should not crash.

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Regression Notes

1. Potential unintended areas of impact

   • None

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

   • Manual testing

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

   --

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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.

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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:	PR is not assigned to a milestone.

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	pr20672-f75300f
	Commit	f75300f60608624fada4a30b613e31a0b78d3309
	Direct Download	jetpack-prototype-build-pr20672-f75300f.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	pr20672-f75300f
	Commit	f75300f60608624fada4a30b613e31a0b78d3309
	Direct Download	wordpress-prototype-build-pr20672-f75300f.apk

Note: Google Login is not supported on these builds.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 40.46%. Comparing base (e87136d) to head (f75300f).

Files	Patch %	Lines
...s/android/ui/posts/EditorJetpackSocialViewModel.kt	0.00%	0 Missing and 2 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## release/24.7 #20672 +/- ## ================================================ - Coverage 40.46% 40.46% -0.01% ================================================ Files 1484 1484 Lines 68416 68417 +1 Branches 11307 11308 +1 ================================================ - Hits 27683 27682 -1 Misses 38233 38233 - Partials 2500 2502 +2 ```

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