mgr/dashboard: Strange iSCSI discovery auth behavior

mgr/dashboard: Strange iSCSI discovery auth behavior

Disable 'autocomplete' for the user and password form fields.

Fixes: https://tracker.ceph.com/issues/46900
Signed-off-by: Volker Theile <vtheile@suse.com>
(cherry picked from commit 4e9c88649de2ac7ea0ad43613fe247f08a623299)

Conflicts:
	src/pybind/mgr/dashboard/frontend/src/app/ceph/block/iscsi-target-discovery-modal/iscsi-target-discovery-modal.component.html
- line 24: span class "invalid feedback" is not available in nautilus, keeping "help-block" instead