Onboarding: setting as default may break import flow

[bsclifton]

Description

Capturing feedback from brave/brave-core#17270

Has not been verified as an issue (yet) - but we should check this. If it's not an issue, we can close this out 😄

Steps to Reproduce

1. Have a browser which isn't Brave registered as the default browser
2. Install Brave (fresh install)
3. In onboarding, accept Brave as the default browser
4. You're prompted to import

Actual result:

Brave is now your default browser - but we should show what USED to be the default browser.

Expected result:

Whatever used to be your default should be the pre-selected choice for importing

[MadhaviSeelam]

Reproduced using STR from #28787 (comment)

Brave | 1.50.107 Chromium: 112.0.5615.39 (Official Build) beta (64-bit)
-- | --
Revision | a0e7b9718a92bcd1cf33b7c95316caff3fc20714-refs/branch-heads/5615@{#753}
OS | Windows 11 Version 22H2 (Build 22621.1413)

Currently user pre-selected default browser (i.e. Edge) is shown on the Import Settings screen when clicked Skip on brave://welcome- first screen. However, when clicked Set Brave as default browser button, user's selection wasn't shown in the Import Settings screen.

Skip	Set Brave as default browser

[kjozwiak]

The above requires 1.50.111 or higher for 1.50.x verification 👍

[GeetaSarvadnya]

Verification PASSED on

Brave | 1.50.113 Chromium: 112.0.5615.49 (Official Build) (64-bit)
-- | --
Revision | bd2a7bcb881c11e8cfe3078709382934e3916914-refs/branch-heads/5615@{#936}
OS | Windows 10 Version 21H2 (Build 19044.2728)

Verified the issue on 1.50.113 and ensured that the user pre-selected default browser (i.e. Edge) is shown as selected on the Import Settings screen when Set Brave as default browser option is selected in the brave://welcome screen

Case 1:

1. Set other browsers (apart from brave) e.g Chrome as default
2. Clean install 1.50.113
3. In brave://welcome screen, select Set Brave as default browser
4. User pre-selected default browser (i.e. Chrome) is shown as selected on the Import Settings screen as expected
5. Ensured that brave is default browser now

step 3	step 4

Case 2:

1. Set other browsers (apart from brave) e.g Edge as default
2. Clean install 1.50.113
3. In brave://welcome screen, select Skip
4. User pre-selected default browser (i.e. Edge) is shown as selected on the Import Settings screen as expected

step 3	step 4