fix(theming): Adjust dark theme to be accessible adjust cypress tests

[susnux]

• Resolves: [BITV] 9.1.4.3/1.1 - The error message "Wrong username or password" does not meet the contrast requirements for text - it is 3,7:1. (1) #41848

Summary

1. Adjust the dark theme colors a bit to have the required contrast for accessibility.
2. Move accessibility cypress test to e2e so all themes can be tested.

Basically on dark mode all status colors had to be made a bit brighter, on bright mode only the warning color failed the tests for the blurry background (but only a little adjustment was needed).

before	after

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[susnux]

BTW unrelated but I noticed that the highcontrast themes are not fulfilling WCAG AAA contrast. I think that should be changed?

[susnux]

/backport to stable28