Bug 30220: Purchase suggestion defaults to first library

Bug 30220: Purchase suggestion defaults to first library

This patch updates the OPAC suggestions form to update the variable
used to pre-select the logged-in user's library.

To test, apply the patch and make sure the "suggestion" preference is
set to "Allow."

- Log in to the OPAC and click "your purchase suggestions" in the
  sidebar menu on your summary page.
- Click "New purchase suggestion."
- The selected library should match the logged-in user's home library.

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>