[#64069] Replace `.hidden-for-sighted` with Primer's `.sr-only`

[myabc]

Ticket

https://community.openproject.org/wp/64069

What are you trying to accomplish?

Replace usages of own hand-rolled hidden-for-sighted class with Primer's sr-only.

See:

• Docs: https://primer.style/css/storybook/?path=/story/utilities-layout--screen-reader-only
• Source: https://github.com/primer/css/blob/main/src/utilities/visibility-display.scss#L96

Screenshots

What approach did you choose and why?

Merge checklist

• [ ] Added/updated tests
• [ ] Added/updated documentation in Lookbook (patterns, previews, etc)
• [ ] Tested major browsers (Chrome, Firefox, Edge, ...)