fix(select): md-focused not removed from options on panel close

[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?

• The focused option's md-focused class is not removed when the menu is closed. When the menu is opened again, another option may be auto focused resulting in two options being decorated with md-focused. Repeating this can lead to many options with md-focused.
• There are no tests for select menu options' focus decoration.

Issue Number:
Fixes #11927

What is the new behavior?

• remove the focused option's md-focused class when the menu is closed
• add tests for select menu options' focus decoration
• improve some JSDoc for interimElement

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information