Remove Twitter row from About screen

[jkmassel]

Summary

• Removes the Twitter/X row from the About screen — tapping it opened a blank webview because X.com doesn't render in an embedded WKWebView

Also cleans up the now-unused TextContent.twitter and Links.twitter constants

Fixes #25493 — reported by @zynp-KC

Test plan

• Open Me → App Settings → About
• Verify the Twitter row is no longer present
• Verify remaining rows (Rate Us, Share, Blog, Legal and More, Work With Us) still function correctly

[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
	Configuration	Release-Alpha
	Build Number	32017
	Version	PR #25496
	Bundle ID	com.jetpack.alpha
	Commit	2ebb207
	Installation URL	3ccrpqjc9o0n8

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 WordPress by scanning the QR code below to install the corresponding build.

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	32017
	Version	PR #25496
	Bundle ID	org.wordpress.alpha
	Commit	2ebb207
	Installation URL	0nhmu1efnt4j8

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