Auto detect token balances when > 0 balance

[bbondy]

It would be best for UX if we can auto detect a user's token balances and auto-add any token that has a balance, instead of making the user add them manually.

We may want to filter out some small balances if there's a lot of noise. This is only for tokens in our registry for now.

[srirambv]

Verification passed on Oppo Reno 5 with Android 12 running 1.46.70 x64 Beta build

• Verified test plan from brave/brave-core#13295
• Verified restoring a wallet via seed shows all tokens that have balance across all accounts
• Verified restoring an account via private key also restores/shows all tokens from that account in addition to already visible tokens
• Verified on a clean wallet only Ethereum and BAT are listed as expected and no other tokens are listed

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Verification passed on Samsung Tab A with Android 10 running 1.46.70 x64 Beta build

• Verified test plan from brave/brave-core#13295
• Verified restoring a wallet via seed shows all tokens that have balance across all accounts
• Verified restoring an account via private key also restores/shows all tokens from that account in addition to already visible tokens
• Verified on a clean wallet only Ethereum and BAT are listed as expected and no other tokens are listed

[srirambv]

Verification passed on

Brave	1.46.81 Chromium: 107.0.5304.68 (Official Build) beta (64-bit)
Revision	a4e93e89d3b3df1be22214603fba846ad0183ca5-refs/branch-heads/5304@{#991}
OS	Linux

• Verified test plan from brave/brave-core#13295
• Verified restoring a wallet via seed shows all tokens that have balance across all accounts
• Verified restoring an account via private key also restores/shows all tokens from that account in addition to already visible tokens
• Verified restoring account via hardware wallet restores all the tokens from the account that have balance
• Verified on a clean wallet only Ethereum and BAT are listed as expected and no other tokens are listed

---

Verification passed on

Brave	1.46.81 Chromium: 107.0.5304.68 (Official Build) beta (64-bit)
Revision	a4e93e89d3b3df1be22214603fba846ad0183ca5-refs/branch-heads/5304@{#991}
OS	Windows 11 Version 22H2 (Build 22621.674)

• Verified test plan from brave/brave-core#13295
• Verified restoring a wallet via seed shows all tokens that have balance across all accounts
• Verified restoring an account via private key also restores/shows all tokens from that account in addition to already visible tokens
• Verified restoring account via hardware wallet restores all the tokens from the account that have balance
• Verified on a clean wallet only Ethereum and BAT are listed as expected and no other tokens are listed

---

Verification passed on

Brave	1.46.81 Chromium: 107.0.5304.68 (Official Build) beta (arm64)
Revision	a4e93e89d3b3df1be22214603fba846ad0183ca5-refs/branch-heads/5304@{#991}
OS	macOS Version 12.6 (Build 21G115)

• Verified test plan from brave/brave-core#13295
• Verified restoring a wallet via seed shows all tokens that have balance across all accounts
• Verified restoring an account via private key also restores/shows all tokens from that account in addition to already visible tokens
• Verified restoring account via hardware wallet restores all the tokens from the account that have balance
• Verified on a clean wallet only Ethereum and BAT are listed as expected and no other tokens are listed