Teacher Tools: Block 'Middle C' border need to be bold in 'Select Block' modal

[v-katherine]

Describe the bug
Teacher Tools: Block 'Middle C' border need to be bold in 'Select Block' modal

Steps to reproduce the behavior
1.Navigate to MakeCode Teacher Tool (microbit.org).
2.Create or open a checklist.
3.Click Add Criteria and 'block used count times'.
4**.Block->Music**, observe the border of 'Middle C'.

Actual behavior:
Mac: The border is not complete
Windows: The border of 'Middle C' is not clear.

Expected behavior:
Should make the border of 'Middle C' bold, or change the background color.

Screenshot:

Additional context:
1.OS: Windows11, iMac Ventura 13.6.6
2.makecode.microbit,org version: 7.0.9
3.Microsoft MakeCode version: 10.0.21