[aria/multiple] Add to and clean up input validation across aria components

[adolgachev]

Added one more validation check for tree when setting multiple values on a single select.
Removed validate method with no checks.

Went through other components and didn't see a practical need for other checks on inputs.

Will do another run-through to see if other mistakes can be validated.

[adolgachev]

This PR was merged into the repository. The changes were merged into the following branches:

• main: dbb94dc
• 21.1.x: ad0aeaa

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