test(material/legacy-chips): fix selectable chips tests (#25790)
test(material/legacy-chips): fix selectable chips tests (#25790)

Fixes that we had some tests where we were testing user selection of a chip, but the chip wasn't set as selectable.
crisbeto/material2,angular/components,crisbeto/material2,angular/components,angular/components,crisbeto/material2,crisbeto/material2,angular/components