Skip sign in when zoomed

[tidy-dev]

xref: https://github.com/github/accessibility-audits/issues/7886

Description

This PR refactors the html/css of the disclaimer in the welcome start screen such that it no longer users absolute positioning, but flex grow property to pin it to the bottom. This makes it so when I added overfow-y scrolling that it will scroll with the rest of the content. Also, found that the use of the zoom property did not allow scrolling and caused content clipping on most welcome flow screens when using minimum hight so I refactored to use scaling to achieve the same affect of the content taking more space for bigger screens.

The above issue only calls out that the "Skip sign in" link is overlapping with other content when minimum screen constraints and 200% zoom. But, after starting working on this I found a few more issues:

1. Due to using zoom scaling based on app width, if you keep the app at min height and expand horizontally you experience the same clipping.
2. On most welcome flow screens (not just start), if you 200% some content and controls is clipped off screen made worse by condition number 1.

CleanShot.2024-05-10.at.09.10.01.mp4

Screenshots

200%

CleanShot.2024-05-10.at.09.16.21.mp4

Scaling:

CleanShot.2024-05-10.at.09.16.21.mp4

Release notes

Notes: [Improved] The welcome start flow content does not overlap or clip when zoomed.

[sergiou87]

After the latest changes, it looks and works great!! Nice cleanup 👏 ✨