Bottom tab improvements: Enable feature flag

[momo-ozawa]

Enables #22325

How to test

• Verify new bottom tab icons are enabled
• Verify icon animation work

Regression Notes

1. Potential unintended areas of impact
   n/a

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)
   n/a

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.

[peril-wordpress-mobile]

	Warnings
⚠️	This PR is assigned to a milestone which is closing in less than 4 days Please, make sure to get it merged by then or assign it to a later expiring milestone

Generated by 🚫 dangerJS

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 24.0 ❄️. The due date for this milestone has already passed. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

Generated by 🚫 Danger

[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	pr22344-7efa1d7
	Version	24.0
	Bundle ID	org.wordpress.alpha
	Commit	7efa1d7
	App Center Build	WPiOS - One-Offs #8368

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	pr22344-7efa1d7
	Version	24.0
	Bundle ID	com.jetpack.alpha
	Commit	7efa1d7
	App Center Build	jetpack-installable-builds #7390

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

[mokagio]

Taking over merging as I'm about to start a new build for 24.0