remove Set default search engine screen for BR / AR

[rebron]

Test plan

See #23814

Description

in brave://welcome remove Set default search engine screen for the following locales: BR / AR

Expected Result

1. Install Brave from the following locales BR / AR
2. Set default search engine screen should be removed from BR / AR (and previously CA / DE / FR / GB / US / AT / ES / MX). Screen should remain for all other locales.
3. Onboarding should be four steps now instead of five.

Brave version (brave://version info)

Target version is 1.45.x maintenance release

Version/Channel Information:

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

Other Additional Information:

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

Miscellaneous Information:

Dependency on #26181
Previous work for removing screen in CA/DE/FR/GB/US here: #18415
Previous work for removing screen in AT / ES / MX here: #23908

[kjozwiak]

Believe the above is Desktop related and not OS/Android. The one for Android re: onboarding will be addressed via #26318.

[kjozwiak]

The above requires 1.45.121 or higher for 1.45.x verification 👍

[kjozwiak]

@brave/qa-team please take a look at brave/brave-core#15669 (comment) for Test Case #1 and basically run through the same thing mentioned via #26181 (comment). Don't run through both BR & AR on one platform. Between the three platforms, both of the new locales will be covered. They've also been checked on Nightly as well before uplifting.

This can also be verified alongside #26181 and can use the format outlined via #26181 (comment).

[stephendonner]

Verified PASSED using

Brave	1.45.121 Chromium: 107.0.5304.91 (Official build) (x86_64)
Revision	3d5948960d62418160796d5831a4d2d7d6c90fa8-refs/branch-heads/5304@{#1097}
ОS	macOS Version 11.7.1 (Build 20G918)

Verification notes can be found in #26181 (comment).

---

Verification PASSED on

Brave | 1.45.121 Chromium: 107.0.5304.91 (Official Build) (64-bit)
-- | --
Revision | 3d5948960d62418160796d5831a4d2d7d6c90fa8-refs/branch-heads/5304@{#1097}
OS | Windows 10 Version 21H2 (Build 19044.2130)

Verification notes can be found in #26181 (comment)

---

Verification passed on

Brave	1.45.121 Chromium: 107.0.5304.91 (Official Build) (64-bit)
Revision	3d5948960d62418160796d5831a4d2d7d6c90fa8-refs/branch-heads/5304@{#1097}
OS	Ubuntu 18.04 LTS

Verification notes can be found in #26181 (comment)