Fix baseline alignment of dropdown-button in Firefox.
Fix baseline alignment of dropdown-button in Firefox.

A previous change added an overflow property to the dropdown-button so that dropdowns don't wrap. But the overflow property, along with inline-flex display and a bunch of other complicated conditions, triggers this bug in Firefox.

It looks like setting a max-width on the dropdown-button is enough to get the desired behavior for material-dropdown-select. So let's do that instead.

Also, add a Scuba test so this alignment stops breaking.

PiperOrigin-RevId: 176144876

angulardart/angular_components,angulardart/angular_components,angulardart/angular_components