Bug 36353: Update relationship value so that it is blank and consistent with other...

Bug 36353: Update relationship value so that it is blank and consistent with other forms

To Test:

1. Choose a User Eligible for a Guarantor:
   1. Modify the user profile to include a new guarantor.
   2. Upon selecting a guarantor, ensure that the empty option in the 'Relationship' dropdown appears as a blank box.

2. Select a User Eligible for a Guarantee:
   1. Navigate to "Add Guarantee" in the top menu.
   2. Verify that the guarantor field is automatically populated with the selected user.
   3. Confirm that the 'Relationship' dropdown displays the empty option as 'Empty record.'

3. Apply Patch and Refresh the Page for Step 2:
   1. After applying the patch, refresh the page for step 2.
   2. Ensure that the empty option value for 'Relationship' is now displayed as blank.

4. Sign Off and Have a Great Day! 😊🎉#

Signed-off-by: Andrew Fuerste Henry <andrewfh@dubcolib.org>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 9de44f00f7744b1ad09ffc0d619344872f81305b)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>