Dashboard banner should size to columns

[cinnamon-msft]

Dev Home version

0.5

Windows build number

No response

Other software

No response

Steps to reproduce the bug

Have a horizontally filled dashboard with the banner visible

Expected result

No response

Actual result

Banner should snap to the column grid sizes

Included System Information

No response

Included Extensions Information

No response

[pehammer]

This would be new feature work