Disable DoT->DoH upgrade when DDR is enabled

When DDR is supported and enabled, DnsResolver will receive dohParams
from ConnectivityService (DnsManager). In that case, disable DoT->DoH
upgrade, as the current hardcoded providers all support DDR already.

This avoids depending on a hardcoded list of providers, making the
feature provider-agnostic, and makes verifying DDR easier as parameters
cannot be obtained through hardcoded values anymore.

Bug: 240259333
Test: manual: verified DoH works with providers supporting DDR
Change-Id: I87a68241119f5486a3c7e7efe4106dd1d41b6ff0