Include year in Traffic date picker

[guarani]

Adds the year to the date picker's display date to avoid confusion about which year is being displayed.

Fixes #22767

Screenshots

Before	After

To test

1. Open Stats
2. Go to the Traffic tab
3. Switch "By day" to different periods and notice the dates include the year (the exact formatting depends on the device locale):
   • By day: January 20, 2024
   • By week: Jan 15 - Jan 21, 2024
   • By year: January 2024

Regression Notes

1. Potential unintended areas of impact

The Traffic tab is the only screen that might be affected

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

Manual testing and existing unit tests.

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

I added unit tests.

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• 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.

Testing checklist:

• Portrait and landscape orientations.
• Light and dark modes.
• Fonts: Larger, smaller and bold text.
• High contrast.
• VoiceOver.
• iPhone and iPad.

[wpmobilebot]

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

	App Name	WordPress Alpha
	Configuration	Release-Alpha
	Build Number	pr22766-29dd5c1
	Version	24.4
	Bundle ID	org.wordpress.alpha
	Commit	29dd5c1
	App Center Build	WPiOS - One-Offs #9070

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[wpmobilebot]

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

	App Name	Jetpack Alpha
	Configuration	Release-Alpha
	Build Number	pr22766-29dd5c1
	Version	24.4
	Bundle ID	com.jetpack.alpha
	Commit	29dd5c1
	App Center Build	jetpack-installable-builds #8113

Automatticians: You can use our internal self-serve MC tool to give yourself access to App Center if needed.

[irfano]

LGTM! The year is now shown with all granularities. I'm approving the PR. I have a minor comment. Feel free to merge after considering my comment. 👍🏻

[guarani]

Hi @mokagio, I've merged this to the release branch to include it as a beta-fix.
Please let me know if you have any questions 🙇