fix(datepicker): remove invalid aria-expanded

[Splaktar]

PR Checklist

Please check that your PR fulfills the following requirements:

• The commit message follows our guidelines
• Tests for the changes have been added or this is not a bug fix / enhancement
• Docs have been added, updated, or were not required

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Enhancement
[ ] Documentation content changes
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

• Lighthouse complains due to the datepicker's input having aria-expanded="false". This properly isn't valid for role="input" in ARIA 1.0 or ARIA 1.1.
• aria-haspopup="true" uses the ARIA 1.0 value.

Issue Number:
Relates to #11475

What is the new behavior?

• remove invalid aria-expanded attribute
• use ARIA 1.1 value for aria-has-popup

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

a11y and keyboard interaction with the md-datepicker and the calendar panel is not good, but testing in VoiceOver showed that these changes didn't make it any worse.