Stats: Add singular strings to weekly roundup notification

[irfano]

Fixes #17824
This fixes using the plural form of "view" and "comment" for singular values on Weekly roundup notifications.

Additionally, this fixes false positive test cases for

• buildNotifications should not include likes and comments with 0 count
• buildNotifications should not include likes with 0 count
• buildNotifications should not include comments with 0 count
• buildNotifications should include views, likes, and comments greater than zero
  in WeeklyRoundupNotifierTest. Before, it was always checking "mock_string" == "mock_string", which was always true.

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To Test:

1. Log in.
2. Ensure one of your top 5 sites has 1 like/comment.
3. Ensure notification permission is allowed.
4. Open Me → Debug settings.
5. Tap the menu button at the top right.
6. Tap "Force show Weekly Roundup notification" button.
7. Wait for a while, ~30 seconds.
8. Tap the Weekly Roundup notification received.
9. Verify that the notification text contains "1 comment" instead of "1 comments" and/or "1 like" instead of "1 likes".

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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)

   • N/A

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

   • Updated WeeklyRoundupNotifierTest.

---

PR Submission Checklist:

• I have completed the Regression Notes.
• I have considered adding accessibility improvements for my changes.
• 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
⚠️	strings.xml files should only be updated on release branches, when the translations are downloaded by our automation.

Generated by 🚫 Danger

[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	pr20608-4f2556b
	Commit	4f2556b
	Direct Download	jetpack-prototype-build-pr20608-4f2556b.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	pr20608-4f2556b
	Commit	4f2556b
	Direct Download	wordpress-prototype-build-pr20608-4f2556b.apk

Note: Google Login is not supported on these builds.

[sonarqubecloud]

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

[codecov]

Codecov Report

Attention: Patch coverage is 69.69697% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 40.39%. Comparing base (b24bac6) to head (4f2556b).

Files	Patch %	Lines
...oid/workers/weeklyroundup/WeeklyRoundupNotifier.kt	69.69%	6 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##            trunk   #20608      +/-   ##
==========================================
- Coverage   40.39%   40.39%   -0.01%     
==========================================
  Files        1474     1474              
  Lines       67906    67920      +14     
  Branches    11226    11231       +5     
==========================================
+ Hits        27433    27438       +5     
- Misses      37994    38000       +6     
- Partials     2479     2482       +3     

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[ravishanker]

LGTM 👍

Fixed a lint issue to merge.