Remove beta badge from Menus and its supporting infrastructure

[nbradbury]

Description

The Menus item on the My Site screen was the only remaining user of the "BETA" badge, and the feature no longer needs the label. This PR removes the badge from Menus and, since nothing else uses it, deletes the entire badge infrastructure to keep things simple — it's easy to reintroduce if a future feature needs it.

Testing instructions

1. Launch the app with a site that has an application password and the edit_theme_options capability (so the Menus item appears)
2. Open the My Site screen

• Verify the Menus item appears without a "BETA" badge

3. Tap the More quick link to open the full menu screen

• Verify the Menus item there also has no badge and rows render correctly

Before shot

[dangermattic]

	1 Warning
⚠️	PR is not assigned to a milestone.

Generated by 🚫 Danger

[wpmobilebot]

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

	App Name	WordPress Android
	Build Type	Debug
	Version	pr22967-a13ba71
	Build Number	1493
	Application ID	org.wordpress.android.prealpha
	Commit	a13ba71
	Installation URL	74gl1o6ip20c8

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

[wpmobilebot]

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

	App Name	Jetpack Android
	Build Type	Debug
	Version	pr22967-a13ba71
	Build Number	1493
	Application ID	com.jetpack.android.prealpha
	Commit	a13ba71
	Installation URL	2t46os2fri2f0

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

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 37.23%. Comparing base (161e21e) to head (a13ba71).

Files with missing lines	Patch %	Lines
...rds/quicklinksitem/QuickLinksItemViewModelSlice.kt	0.00%	1 Missing ⚠️
...id/ui/mysite/items/listitem/SiteListItemBuilder.kt	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            trunk   #22967   +/-   ##
=======================================
  Coverage   37.22%   37.23%           
=======================================
  Files        2329     2329           
  Lines      125323   125306   -17     
  Branches    17044    17043    -1     
=======================================
- Hits        46657    46653    -4     
+ Misses      74893    74880   -13     
  Partials     3773     3773           

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