Tweaks to the core update page

Problem/Motivation

Related to 📌 Update tab and page title to be more clear Active the 'Update' and 'Update extensions' tabs are a bit confusing, it's not obvious that one is for core only. There are some other slightly odd things about this page that we could try to fix too.

Admittedly the entire 'Extend' section needs a UX overhaul; I don't want to try to solve this here, so am proposing a minor tweaks only.

Current page:

Proposed resolution

TBC

Remaining tasks

TBC

User interface changes

TBC