Overview: 
When we using find-user plugin to choose patron, sometimes focus jumps on plugin button instead of item barcode input.

Steps to Reproduce:

1. First of all you should have fast internet connection (other way it's not reproducible)

2. Go to checkout module

3. Choose patron with using of Patron look-up button

If bug was not reproduced, try to choose another patron, or the same patron few more times.

Expected Results:

After patron was choosen, focus should automatically jump on item barcode input.

Actual Results:

Sometimes focus jumps on Patron look-up button.

Additional Information:
To resolve issue with focus, additionally to changes in ui-plugin-find-user we should add prop passing in ui-checkout module.
Corresponding ticket for {{ui-plugin-find-user}}: https://folio-org.atlassian.net/browse/UIPFU-48