Only specify net::HostResolverSource::DNS when DoH is enabled (uplift to 1.23.x)

[brave-builds]

Uplift of #8279
Resolves brave/brave-browser#14755

Pre-approval checklist:

• You have tested your change on Nightly.
• This contains text which needs to be translated.
  • There are more than 7 days before the release.
  • I've notified folks in #l10n on Slack that translations are needed.
• The PR milestones match the branch they are landing to.

Pre-merge checklist:

• You have checked CI and the builds, lint, and tests all pass or are not related to your PR.

Post-merge checklist:

• The associated issue milestone is set to the smallest version that the changes is landed on.

[kjozwiak]

test-browser failed on Linux as per https://ci.brave.com/job/pr-brave-browser-pr8279_cname-adblock-doh_1.23.x-linux/1/execution/node/241/log/ & https://ci.brave.com/job/pr-brave-browser-pr8279_cname-adblock-doh_1.23.x-linux/1/execution/node/244/log/. However, this is a known issue and not related to this specific PR.

13:59:44  5 tests crashed:
13:59:44      BraveStatsUpdaterBrowserTest.StatsUpdaterMigration (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:275)
13:59:44      BraveStatsUpdaterBrowserTest.StatsUpdaterSetsFirstCheckPreference (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:154)
13:59:44      BraveStatsUpdaterBrowserTest.StatsUpdaterStartupPingWithDefaultReferralCode (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:229)
13:59:44      BraveStatsUpdaterBrowserTest.StatsUpdaterStartupPingWithReferralCode (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:327)
13:59:44      BraveStatsUpdaterBrowserTest.StatsUpdaterThresholdSetsFirstCheckPreference (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:191)

Restarting macOS due to https://ci.brave.com/job/pr-brave-browser-pr8279_cname-adblock-doh_1.23.x-macos/1/execution/node/164/log/.

14:32:44  FAILED: obj/chrome/browser/devtools/devtools/cast_handler.o 

Looks like post-init failed audit_deps as per https://ci.brave.com/job/pr-brave-browser-pr8279_cname-adblock-doh_1.23.x-post-init/1/execution/node/144/log/. However, this is a known issue and will be fixed via #8276. I don't think there's a need to rebase the PR.

[kjozwiak]

Waiting on https://github.com/brave/brave-browser/releases/tag/v1.24.6 which we'll need to check the above on Nightly.

[kjozwiak]

test-browser failed on Linux as per https://ci.brave.com/job/pr-brave-browser-pr8279_cname-adblock-doh_1.23.x-macos/4/execution/node/242/log/ & https://ci.brave.com/job/pr-brave-browser-pr8279_cname-adblock-doh_1.23.x-macos/4/execution/node/245/log/. However, this is a known issue and not related to this specific PR.

00:43:40  5 tests crashed:
00:43:40      BraveStatsUpdaterBrowserTest.StatsUpdaterMigration (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:275)
00:43:40      BraveStatsUpdaterBrowserTest.StatsUpdaterSetsFirstCheckPreference (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:154)
00:43:40      BraveStatsUpdaterBrowserTest.StatsUpdaterStartupPingWithDefaultReferralCode (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:229)
00:43:40      BraveStatsUpdaterBrowserTest.StatsUpdaterStartupPingWithReferralCode (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:327)
00:43:40      BraveStatsUpdaterBrowserTest.StatsUpdaterThresholdSetsFirstCheckPreference (../../brave/browser/brave_stats/brave_stats_updater_browsertest.cc:191)

[kjozwiak]

Uplift into 1.23.x approved after deliberating with @brave/uplift-approvers. QA has verified the PR on Nightly as per #8279 (comment).