Do not show opt-in page for decentralized DNS support in OTR contexts

[yrliou]

Description

It's better to just limit the opt-in of decentralized DNS support in normal profiles.
Note that this does not mean that we can not have the resolution support in private and guest windows, it can be used normally if user already opts in the normal profile.
Resolution in Tor is not supported.

Steps to Reproduce

1. Set resolve methods for Unstoppable Domains and ENS to Ask.
2. Visit brave.crypto and brantly.eth in the normal window should see opt-in interstitial pages.
3. Open private, private with Tor, and guest window.
4. Visit brave.crypto and brantly.eth in private, private with Tor, and guest window should not see opt-in interstitial page.

Actual result:

Currently we're able to see interstitial pages in step 4.

Expected result:

Should not see interstitial pages in step 4.

Reproduces how often:

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release?
• Can you reproduce this issue with the beta channel?
• Can you reproduce this issue with the nightly channel?

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

[stephendonner]

Verified PASSED using the inline testplan on nightly build

Brave	1.23.33 Chromium: 89.0.4389.86 (Official Build) nightly (x86_64)
Revision	0c2dac31bc21e806a791641316e99920f84ea52c-refs/branch-heads/4389@{#1472}
OS	macOS Version 11.2.3 (Build 20D91)

1. Set resolve methods for Unstoppable Domains and ENS to Ask.
2. Visited brave.crypto and brantly.eth in the normal window should see opt-in interstitial pages.

Verified: (Normal Tab)

3. Open private, private with Tor, and guest window.
4. Visit brave.crypto and brantly.eth in private, private with Tor, and guest window should not see opt-in interstitial page.

Verified: (Private, Private with Tor)

Verified: (Guest Mode)

---

Verification passed on

Brave | 1.22.66 Chromium: 89.0.4389.90 (Official Build) (64-bit)
-- | --
Revision | 62eb262cdaae9ef819aadd778193781455ec7a49-refs/branch-heads/4389@{#1534}
OS | Windows 10 OS Version 2004 (Build 19041.867)

• Verified the STR from the description Do not show opt-in page for decentralized DNS support in OTR contexts #14488 (comment)

Normal Tab:
Ensured that open brave.crypto and brantly.eth in the normal window is showing the opt-in interstitial pages.

brave.crypto	brantly.eth

Private Tab or Private windows with TOR or Guest window:
Ensured that open brave.crypto and brantly.eth in PT or Private window with TOR or Guest window isn't showing the opt-in interstitial pages.

PT

brave.crypto	brantly.eth

Private windows with TOR

brave.crypto	brantly.eth

Guest window

brave.crypto	brantly.eth

---

Verification passed on

Brave	1.22.66 Chromium: 89.0.4389.90 (Official Build) (64-bit)
Revision	62eb262cdaae9ef819aadd778193781455ec7a49-refs/branch-heads/4389@{#1534}
OS	Ubuntu 18.04 LTS

normal window shows opt-in interstitial pages.

private window, private window with tor, guest window does not show opt-in interstitial pages