fix #1055 option stayed selected in Select after removal from options list

This is a follow-up of PR #1218

I've changed the test scenario from the first one to the second one reported in #1055 and added some more asserts (the first one was no longer reproducible since it was fixed in 1.6.5, moreover the second scenario was better showing the issue).

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When `@aria:Select` options were bound to the data model,
and the currently selected option was removed from the option list
through the binding, it still remained as the data model value
of the widget (although no longer available in the UI).

Close #1218
Close #1309