fix(image-upload): increase text contrast for accepted files string to meet accessibility standards

[kristinalustig]

Describe your changes

Updating the text contrast for the accepted file types string so that it meets accessibility standards for contrast.

PR Checklist

• All new/changed functionality includes unit and (optionally) e2e tests as appropriate
• All new/changed functions have /** ... */ docs
• I've added the bug/enhancement and other labels as appropriate

Additional context

Matches a change in SO editor.

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[giamir]

@kristinalustig the color contrast for the "caption" element is already passing our accessibility standard. This would be a cosmetic change rather than an accessibility fix.

Before (black-400 - APCA Lc76)

After (black-500 - APCA Lc94)

Lc76 already passes our Lc60 target for text.

@kristinalustig Could you add a reference to a ticket? I believe a designer was consulted for making this change.
If not perhaps @CGuindon could give us the thumbs up on the change.

Thank you.

[CGuindon]

Yup, black-400 passes on our background and I would actually prefer to keep it at 400 instead of changing to 500. That way we only have 2 different shades of black in that small area instead of 3 (primary and secondary text). @kristinalustig

[giamir]

@kristinalustig based on @CGuindon's last comment can we close this PR?

[kristinalustig]

@giamir whoops, sorry for the delayed response, this PR got lost in the shuffle. Looks like we don't have to make this change, then. It's fine to close this PR. thanks @CGuindon for weighing in.