Remove usage of base::internal::MakeUnboundRunType

Chromium removes base::internal::MakeUnboundRunType in
https://crrev.com/c/5110744. Remove the usage, and use auto and template
deduction guides instead.

Bug: 316060144
Tag: #floss
Flag: EXEMPT, no logical change. Done for compatibility with Floss.
Test: emerge floss in cros_sdk
Test: m Bluetooth
Change-Id: I35f5f29c70dcb0084f3a60331fd73cb93760c46d