fix(#2333): ensure dropdown items are kept in sync when changed

[chrisolsen]

When changing dynamically bound dropdown items, if the items are reduced and no new items are added, the dropdown items would not change.

Before (the change)

• Bind the values [red, green, blue], view the dropdown items to see the 3 items
• Bind the value [red], you will still see the three previously bound items

After (the change)

• Bind the values [red, green, blue], view the dropdown items to see the 3 items

• Bind the value [red], you will now just see red

• Browser tests written

• Tested in React

• Tested in Angular

• Tested Web components

# checkout then run the browser tests, they should fail
git checkout HEAD~2
npx vitest --project=*-headless --run

# checkout the fixes, tests should now pass
git checkout chris/2333-dropdown-reset
npx vitest --project=*-headless --run

Steps needed to test