Change Windows Powershell default scheme to Campbell

[carlos-zamora]

Summary of the Pull Request

The "Campbell Powershell" color scheme does not have a high enough color contrast ratio. Campbell does, so we're changing it there.

PR Checklist

• Will close issue A11y_Windows Terminal_Open any Application_Color Contrast: While Opening any application which is not existing then the error message will be displayed and it is not meeting the color contrast ratio 4.5:1 #5393 upon verification

Validation Steps Performed

[DHowett-MSFT]

This magic word will trigger a close.

[carlos-zamora]

This magic word will trigger a close.

The key is to make it look similar, but confuse GitHub's bot haha

[ghost]

🎉Windows Terminal Preview v0.11.1121.0 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Store Download