fix(multiselect): set optional chaining for undefined multiselect

[jesnajoseijk]

Closes #16052

Added optional chaining for undefined multi select value

Changelog

New

• {{new thing}}

Changed

• multiselect.tsx

Removed

• {{removed thing}}

Testing / Reviewing

{{MultiSelect component}}

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[jesnajoseijk]

I have read the DCO document and I hereby sign the DCO.

[jesnajoseijk]

recheck

[jesnajoseijk]

closing since a new PR is raised