fix(ngAria): do not scroll when pressing spacebar on custom buttons

By default, pressing spacebar causes the browser to scroll down.
However, when a native button is focused, the button is clicked instead.

`ngAria`'s `ngClick` directive, sets elements up to behave like buttons.
For example, it adds `role="button"` and forwards `ENTER` and `SPACEBAR`
keypresses to the `click` handler (to emulate the behavior of native
buttons).

Yet, pressing spacebar on such an element, still invokes the default
browser behavior of scrolling down.

This commit fixes this, by calling `preventDefault()` on the keyboard
event, thus preventing the default scrolling behavior and making custom
buttons behave closer to native ones.

Closes #14665

Closes #16604