[CrOS PhoneHub] Update BleScanner to support multiple mediums

BleScanner scans for incoming BLE advertisements but only notifies
observers of results once they have been filtered by parameters provided
by clients. Before this CL, a filter consisted of a DeviceIdPair and a
ConnectionRole.

We will be utilizing BleScanner for Phone Hub, so now it must also
filter by ConnectionMedium. Since ConnectionAttemptDetails objects
consist of a DeviceIdPair, a ConnectionMedium, and a ConnectionRole
(i.e., exactly what we need), this CL change the type of the scan filter
parameters with ConnectionAttemptDetails.

A TODO is added in ble_scanner_impl.cc to reflect the fact that we must
now include the medium as part of the filtering process. This is left
for a follow-up CL.

Bug: 1106937
Change-Id: I251fe812b87145ae9861140af7021dfe2530084b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2392954


Commit-Queue: Kyle Horimoto <khorimoto@chromium.org>
Reviewed-by: James Vecore <vecore@google.com>
Cr-Commit-Position: refs/heads/master@{#805187}