Update upgrade-ubuntu article for 24.04

[ahoneybun]

This updates all of the screenshots.

[XV-02]

This will also need some edits to content:

• Omit references to DVDs as install media. The Ubuntu desktop ISO has exceeded single-layer DVD size since 22.04, and is now considerably larger than a single-layer DVD.
• In other articles we reference the lower left-hand 'show apps' button. This is present on Ubuntu 22.04 and 24.04. Instead of Open the Activities Overview by clicking on the Activities button in the top left and then search for Software Updater. we should reference the 'show apps' button. This is due to Gnome making the activities button unintuitive beginning with version 45, where it transitioned from an immediately identifiable word to ~~an immediately blobby blob of blobiness that communicates blobularity with blobbing aplomb~~ a less identifiable workspace indicator. In contrast, we can establish the 'show apps' paradigm across multiple articles, and benefit from it looking like it might actually be a normal interactable.
• We should highlight that the Updater may run for a moment before presenting the settings button referred to in the Configure Version Updates step.
• ~~Most other guides I have seen recommend making sure system packages are fully up to date before doing a release upgrade. We may wish to do the same.~~ Never mind. already there :sweat_smile:

Sure there are a few others, but that's what I have for now.