update search engine onboarding screen

[rebron]

Description

Update search engine onboarding screen graphic and text.

Current result:

Updated Design and Expected result:

Figma link for assets:
https://www.figma.com/file/MFHpcXJMg2RUQpUJMAZZ4R/Desktop-Onboarding?node-id=2182%3A35486

Brave version (brave://version info)

Targeted for 1.27.x

Version/Channel Information:

n/a

• 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:

cc: @karenkliu

[GeetaSarvadnya]

Verification passed on

Brave | 1.27.107 Chromium: 92.0.4515.107 (Official Build) (64-bit)
-- | --
Revision | 87a818b10553a07434ea9e2b6dccf3cbe7895134-refs/branch-heads/4515@{#1634}
OS | Windows 10 OS Version 2004 (Build 19041.1110)

• Verified the Figma doc https://www.figma.com/file/MFHpcXJMg2RUQpUJMAZZ4R/Desktop-Onboarding?node-id=2182%3A35692 and ensured the below:
  • Confirmed search box favicon is changed as mentioned in the Figma doc
  • Confirmed the search onboarding slide text changed to Choose the search engine you would like to use by default when searching the web from the address bar.

• Additional testing is covered in https://github.com/brave/internal/issues/789#issuecomment-884992237