Fix the bad default light theme selection background color

[uoRetr0]

Summary of the Pull Request

Fixed default selection background colors with light schemes. Default color now matches the scheme and contrasts well

References and Relevant Issues

none

Detailed Description of the Pull Request / Additional comments

This is my first contribution ever :) Even though its simple, im happy to help

Validation Steps Performed

PR Checklist

• Closes Bad default selection background color with light schemes #8716
• Tests added/passed
• Documentation updated
  • If checked, please file a pull request on our docs repo and link it here: #xxx
• Schema updated (if necessary)

[DHowett]

You submitted this pull request at just the right time! We finally fixed a long-standing issue where changes to the default color schemes would be ignored for existing users. Thanks!

We'll get this reviewed ASAP

[zadjii-msft]

OneHalf light:

Solarized:

Tango:

[zadjii-msft]

You know, I think we technically already did this over in #16243. When that PR was authored, it didn't get linked up to #8716 quite right, so it didn't get closed.

I'm fine merging this, as the new colors are still good too