Recovery phrase verification should use randomized word indices

[josheleonard]

Description

brave/brave-core#13146 (comment)
When creating a new wallet during onboarding, the user is always asked to verify the first, third, and last words of their recovery phase.
We should randomize these words to deter users from not properly backing-up their recovery phrase

Steps to Reproduce

1. Reset Wallet
2. Create New Wallet
3. Continue to the Verify recovery phrase onboarding step

Actual result:

The user is only ever asked to verify the first, third and last words of their recovery phrase

Expected result:

The user is asked to verify 3 randomly selected words from their recovery phrase

cc @kdenhartog

[srirambv]

Verification passed on

Brave	1.44.95 Chromium: 106.0.5249.40 (Official Build) (64-bit)
Revision	fab1d91915d2722d6339aaa7f4e9ce44f1e9b103-refs/branch-heads/5249@{#442}
OS	Linux

• Verified steps from brave/brave-core#14633
• Verified recovery phrase verification has randomized word indices for each wallet creation

24683-Linux.mp4

---

Verification passed on

Brave	1.44.95 Chromium: 106.0.5249.40 (Official Build) (64-bit)
Revision	fab1d91915d2722d6339aaa7f4e9ce44f1e9b103-refs/branch-heads/5249@{#442}
OS	Windows 11 Version 21H2 (Build 22000.978)

• Verified steps from brave/brave-core#14633
• Verified recovery phrase verification has randomized word indices for each wallet creation

24683-Windows.mp4

---

Verification passed on

Brave	1.44.95 Chromium: 106.0.5249.40 (Official Build) (arm64)
Revision	fab1d91915d2722d6339aaa7f4e9ce44f1e9b103-refs/branch-heads/5249@{#442}
OS	macOS Version 12.4 (Build 21F79)

• Verified steps from brave/brave-core#14633
• Verified recovery phrase verification has randomized word indices for each wallet creation

24683-macOS.mov