TaxonomyPicker validate empty value if required is set to true

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Category

[x ] Enhancement

[ ] Bug

[ ] Question

Expected / Desired Behavior / Question

If you set required property to true on TaxonomyPicker the validation schould occur and call onGetErrorMessage,

Observed Behavior

Right now required property is only for showing asterisk on label.

Steps to Reproduce

<TaxonomyPicker
allowMultipleSelections={false}
termsetNameOrID="guid"
panelTitle="Title"
placeholder="Pick"
label=""
required={true}
onGetErrorMessage={(value: IPickerTerms) => {
return errorMessage;
}}
context={spfxContext as any}
onChange={(val) => {
console.log(val);
item.tegund = val;
}}
initialValues={[]}
validateInput={true}
validateOnLoad={true}
/>
TaxonomyPicker is added to onRender and errorMessage is static string with just error text.
onGetErrorMessage never launches when control is loosing focus etc.

Start by locating the TaxonomyPicker implementation and its handling of required, validateInput, validateOnLoad, and onGetErrorMessage. Reproduce the provided empty-value example and trace what happens when the control loses focus. Done means required empty values trigger the supplied validation callback as expected.