fix(material-experimental/mdc-select): panel losing max-height if menu is opened after select (#21341)
fix(material-experimental/mdc-select): panel losing max-height if menu is opened after select (#21341)

If an MDC-based `mat-menu` is opened after a `mat-select`, the select will lose
its `max-height`, because its selector specificity is too low and it gets overwritten
by the menu which uses the same set of mixins.

These changes resolve the issue by increasing the specificity.
crisbeto/material2,andrewseguin/material2,angular/components,josephperrott/material2,angular/components,DevVersion/material2,josephperrott/material2,mmalerba/material2,angular/components,crisbeto/material2,crisbeto/material2,mmalerba/material2,andrewseguin/material2,mmalerba/material2,angular/components,josephperrott/material2,DevVersion/material2,andrewseguin/material2,DevVersion/material2,andrewseguin/material2,josephperrott/material2,DevVersion/material2,mmalerba/material2,josephperrott/material2,andrewseguin/material2,DevVersion/material2,mmalerba/material2,crisbeto/material2