Do not prompt user to backup seed phrase when wallet is imported

[srirambv]

Description

Do not prompt user to backup seed phrase when wallet is imported

Steps to Reproduce

1. Enable wallet flag
2. Restore wallet using a seed phrase
3. Upon restore backup wallet message is shown
4. Dismiss notification and reload the page, notification shows up again

Actual result:

Backup wallet notification is shown even when a user has restored wallet using seed words

Expected result:

Do not prompt user to backup seed phrase when wallet is imported using seed words

Reproduces how often:

Easy

Brave version (brave://version info)

Brave	1.33.10 Chromium: 95.0.4638.50 (Official Build) nightly (x86_64)
Revision	3e9db37693d0cf8e31a89fbcf50401ae91125cef-refs/branch-heads/4638@{#816}
OS	All

Version/Channel Information:

• Can you reproduce this issue with the current release? NA
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? NA
• Does the issue resolve itself when disabling Brave Rewards? NA
• Is the issue reproducible on the latest version of Chrome? NA

Miscellaneous Information:

cc: @jamesmudgett @Douglashdaniel