AutocompleteWidget: SelectedOptions are not mutated on property changes

[VincentKneip]

Currently, the selectedOptions array within AutocompleteWidget does not get changed when widget properties like api or hasShortSelectedLabel are adjusted. This leads to the following inconveniences:

• setting allowCustomTerms from true to false does not remove already selected custom terms
• changing the boolean value of hasShortSelectedLabel does not alter the label length of already selected terms
• setting singleSelection from false to true writes the selected terms into one single term label
• changing the parameter or api string does not apply changes to the already selected terms

If changing the widget properties dynamically is an intended feature, the inconveniences should be removed by re-querying and storing more information about the selected terms (e.g. whether they are custom terms, and their long and short label form). Is changing the widget properties dynamically intended, or just a feature in the Storybook, which won't appear in real applications?

[VincentKneip]

The implementation of this issue might be too complicated and not really necessary.

We suggest to just clear all selected terms on property changes.

[VincentKneip]

Added the functionality in this commit. When feat/plainJS-sb-integration is merged, this issue can be closed.