feat(mat-checkbox): add original click event in MatCheckboxChange

[moniuch]

Feature Description

In order to be able to conditionally process MatCheckboxChange event depending on the keyboard modifiers, I'd like to request that the original event be also included.

Most probably this request could also apply to mat-radio, haven't checked (pun intended!).

Use Case

No response

[moniuch]

can use (click)