fix(wallet): Fixed legacy wallet imports

[muliswilliam]

Resolves brave/brave-browser#38074

Submitter Checklist:

• I confirm that no security/privacy review is needed and no other type of reviews are needed, or that I have requested them
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally:
  • npm run test -- brave_browser_tests, npm run test -- brave_unit_tests wiki
  • npm run presubmit wiki, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

Screen.Recording.2024-05-13.at.19.52.45.mov

[Douglashdaniel]

++

[mkarolin]

strings++

[brave-builds]

A Storybook has been deployed to preview UI for the latest push

[brave-builds]

A Storybook has been deployed to preview UI for the latest push

[brave-builds]

A Storybook has been deployed to preview UI for the latest push

[srirambv]

Verification passed on

Brave	1.68.39 Chromium: 125.0.6422.76 (Official Build) nightly (64-bit)
Revision	8d3c424
OS	Linux

• Verified steps from issue description
• Verified Legacy wallet import option is shown during onboarding
• Verified able to import legacy wallet into new wallet without any issue

23609.mp4