mat-select-panel is missing border radius in Phone Number Format

[ektasawant]

Describe the bug

mat-select-panel is missing border radius in Phone Number Design pattern.

What is the expected behavior?

mat-select-panel is should have border-radius: 4px.

What are the steps to reproduce?

1. Go to http://localhost:4200/forms-and-validation/phone-number-format
2. Click on Country Code dropdown
3. Observe mat-select panel

Screenshots or links to minimum reproduction example

Environment

All