Fix search feature unresponsive after setting an empty list

[gnbm]

• This PR aims to fix the issue Search Feature Unresponsive After Setting an Empty List of Options #318
• When using dropdown with the search feature on, the search feature became unresponsive after setting an empty options list.

What was happening

• To replicate it:
  1. Open the dropdown and click on the Search input
  2. Checked we can type there and sort the list
  3. Click on Remove All
  4. Open the dropdown and click on the Search input
  5. Checked that it is disabled as expected since the options list has no options
  6. Click on Fill
  7. Open the dropdown and click on the Search input
  8. Checked that it is incorrectly disabled

After the fix

• The fix was on the method focusElementOnOpen()
• To replicate it:
  1. Open the dropdown and click on the Search input
  2. Checked we can type there and sort the list
  3. Click on Remove All
  4. Open the dropdown and click on the Search input
  5. Checked that it is disabled as expected since the options list has no options
  6. Click on Fill
  7. Open the dropdown and click on the Search input
  8. Checked we can type there and sort the list

• Followed the same steps above - ✅
• Ran regression scenarios - ✅
• Run automated tests - ✅