Some IPFS DOH Fixes

[cypt4]

1. Remove IPFS DOH DNS override when user switches DOH off.
2. Remove {?dns} from the url in DNS.Resolvers, because lib-p2p only uses POST requests.

Fixes brave/brave-browser#24678
Fixes brave/brave-browser#24706

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https:/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https:/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https:/brave/brave-browser/wiki/Fingerprinting-Protections
  • https:/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https:/brave/brave-browser/wiki/Custom-Headers
  • https:/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https:/brave/brave-browser/wiki/QA-Guide
  • https:/brave/brave-browser/wiki/P3A

Test Plan:

For brave/brave-browser#24678
Enable DOH, check brave_ipfs/config file in the browser's data folder. Make sure there is DNS.Resolvers property
Disable DOH, check the config again. Make sure there is no DNS.Resolvers property.

For brave/brave-browser#24706
Make sure that DOH override works for Google DNS which is using {?dns} template url.
Before check also it is needed to modify brave_ipfs/config to remove non-dnsname bootstrap urls.

[yrliou]

LGTM

[stephendonner]

1. Issue Remove DNS.Resolvers IPNS config property if user disables DOH brave-browser#24678: filed DNS resolver doesn't get reset after enabling, then disabling, DoH for IPNS brave-browser#24900

2. Verified PASSED using

Brave	1.44.62 Chromium: 104.0.5112.102 (Official Build) nightly (x86_64)
Revision	8e5396254975ef939f2ef7d0bd334e48a052b536-refs/branch-heads/5112@{#1478}
OS	macOS Version 11.6.8 (Build 20G730)

1. install 1.44.62
2. launch Brave
3. load brave://ipfs-internals/
4. click on Install and start
5. chose Google DNS as a DoH provider in brave://settings/security
6. removed the following from {profile_folder}/brave_ipfs/config

"/ip4/104.131.131.82/tcp/4001/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ","/ip4/104.131.131.82/udp/4001/quic/p2p/QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ",

7. loaded ipns://ipfs.io
8. clicked Use a Brave IPFS node

Confirmed I was able to load ipns://ipfs.io

example	example	example	example