le_scanning_manager: Ignore Scan Response when Passive scanning

By definition Passive scanning won't send out SCAN_REQ PDUs so shouldn't
wait for Scan Response.

This patch only affects the ChromeOS device using Legacy scan because
it's the only use case of LeScanningFilterPolicy::ACCEPT_ALL + Passive;
On the other platforms Vendor command + FILTER_ACCEPT_LIST_ONLY is
usually preferred.

Bug: 323979740
Tag: #floss
Test: mmm packages/modules/Bluetooth
Test: Manual & Tauto test with https://r.android.com/c/2952830
Flag: EXEMPT, Floss-only changes because Android always uses Active scan
Change-Id: I8277abad492a06a60810d44066043b14c235b8c4