fix(radio): only show focus ripple for keyboard focus (#13565)

After the switch to the latest Material Design spec, we started showing the focus ripple for all kinds of focus, however it's only supposed to be for keyboard focus.

Fixes #13544.

Author: crisbeto

src/lib/radio/radio.scss

@@ -150,7 +150,7 @@ $mat-radio-ripple-radius: 20px;
     opacity: 0.04;
   }
 
-  .mat-radio-button:not(.mat-radio-disabled).cdk-focused & {
+  .mat-radio-button:not(.mat-radio-disabled).cdk-keyboard-focused & {
     opacity: 0.12;
   }