Bug 35350: Update label creator pop-up windows with consistent footer markup

Bug 35350: Update label creator pop-up windows with consistent footer markup

This patch updates two label creator templates in order to style
submission and close buttons in a fixed footer at the bottom of the
window, with markup consistent with other pop-up windows.

To test, apply the patch and go to Cataloging -> Label creator.

- Click New -> Label batch.
- Click the "Add items" button under the form.
- A "Search for items" window should pop up.
  - The window's fixed footer should have the "Search" and "Close
    window" buttons. Test that each work correctly.
- Submit a search which will return results.
  - The search results window should also have a fixed footer. I moved
    the "Add checked" and "Done" buttons out of a floating toolbar and
    put the controls there for consistency's sake.
  - Confirm that both controls work correctly.

Signed-off-by: Barbara Johnson <barbara.johnson@bedfordtx.gov>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit f1e9c6e95985b8a7439ad0e7e0a9df688fbdc1c2)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>