Consolidate Reader navigation

[kean]

Update Reader navigation in Jetpack to match the standalone app. This way, it's easier to find the main navigational areas. The convenience "Subscriptions", "Tags", and "Lists" sections below no longer contains any main navigational areas or actions – only convenient access for individual items.

Before / After

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 26.0. The due date for this milestone has already passed. Please assign it to a milestone with a later deadline or check whether the release for this milestone has already been finished.

Generated by 🚫 Danger

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[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	28080
	Version	PR #24650
	Bundle ID	org.wordpress.alpha
	Commit	a173eef
	Installation URL	46t9brlf1tt7g

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

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	28080
	Version	PR #24650
	Bundle ID	com.jetpack.alpha
	Commit	a173eef
	Installation URL	3c83omhatqjto

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