[Android] Update search engine defaults for BR / AR

[timchilds]

Description

Update search engine defaults for:

• Brazil (BR)
• Argentina (AR)

Brave should be at the top of drop down list at settings -> search engines.

Related: #18331, #23814 and #26181

Test plan

Region set to BR / AR

1. Fresh profile
2. Search onboarding should NOT be shown
3. Default search engine SHOULD be Brave
4. Visit settings -> search engines
5. Brave SHOULD be first in the Default search engines list

Region set to anything else (excluding CA / DE / FR / GB / US / AT / ES / MX)

1. Fresh profile
2. Search onboarding SHOULD be shown
3. Default will NOT be Brave Search
4. Visit settings -> search engines
5. Brave SHOULD be first in the Default search engines list - unless you're in a region where Yandex is default (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM, UZ). In that case it will be second.

Notes for test plan

#23814 (comment)

[kjozwiak]

As per #26181 (comment), we basically need to change the onboarding behaviour for BR & AR. Believe we remove the onboarding when the user taps on the URL. We're currently displaying it.

[kjozwiak]

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

[Uni-verse]

Verified on Samsung Galaxy S21 & Samsung Galaxy Tab S7 using the following build(s):

Brave	1.45.125 Chromium: 107.0.5304.110 (Official Build) (64-bit) 
Revision	2a558545ab7e6fb8177002bf44d4fc1717cb2998-refs/branch-heads/5304@{#1202}
OS	Android 12; Build/SP1A.210812.016

Test Plan: brave/brave-core#15783 (comment)

AR (Argentina) locale (New addition)

• Ensured Brave is default SE for normal tabs
• Ensured Brave is default SE for private tabs
• Ensured SE onboarding is removed

Example	Example	Example	Example

BR (Brazil) locale (New addition)

• Ensured Brave is default SE for normal tabs
• Ensured Brave is default SE for private tabs
• Ensured SE onboarding is removed

Example	Example	Example	Example

DE (Germany) Existing Brave Default SE

• Ensured Brave is default SE for normal tabs
• Ensured Brave is default SE for private tabs
• Ensured SE onboarding is removed

Example	Example	Example

CO (Columbia) Existing Non-Brave Default SE

• Ensured default SE for normal tabs is set as Google
• Ensured default SE for private tabs is set as Google
• Ensured tapping on the URL on the second attempt displays the SE onboarding modal without issues
• Ensured Google is selected as the default SE via the onboarding modal
• Ensured Normal & Private SE are updated correctly if another SE is selected from the onboarding modal

Example	Example	Example	Example	Example

Yandex Default SE (RU) Locale

• Ensured Default SE is set to Yandex for normal and private tabs
• Ensured SE Onboarding is displayed
• Ensured that SE settings are updated accordingly after selecting SE from onboarding modal

Example	Example	Example	Example