Virtualize Tokens List

[josheleonard]

Description

The current Tokens list implementation renders the entire list, even if the majority of the list is not visible within the viewport

Steps to Reproduce

Scenario 1

1. Visit brave://wallet/crypto/deposit-funds
2. Scroll down the list of assets

Scenario 2

1. Add many assets to the visible tokens list (including multiple NFTs)
2. Scroll down the list of assets on the portfolio page
3. Sort, search and filter the list

Actual result:

List takes a long time to render

Expected result:

List renders/scrolls smoothly

[srirambv]

Verification passed on

Brave	1.45.95 Chromium: 106.0.5249.103 (Official Build) beta (64-bit)
Revision	182570408a1f25ab2731ef5f283b918df9b9f956-refs/branch-heads/5249_91@{#6}
OS	Linux

• Verified steps from issue description and brave/brave-core#14817
• Verified there is smooth scroll on deposit screen
• Verified smooth scroll on portfolio with tokens and NFT's

---

Verification passed on

Brave	1.45.95 Chromium: 106.0.5249.103 (Official Build) beta (64-bit)
Revision	182570408a1f25ab2731ef5f283b918df9b9f956-refs/branch-heads/5249_91@{#6}
OS	Windows 11 Version 21H2 (Build 22000.978)

• Verified steps from issue description and brave/brave-core#14817
• Verified there is smooth scroll on deposit screen
• Verified smooth scroll on portfolio with tokens and NFT's

---

Verification passed on

Brave	1.45.95 Chromium: 106.0.5249.103 (Official Build) beta (arm64)
Revision	182570408a1f25ab2731ef5f283b918df9b9f956-refs/branch-heads/5249_91@{#6}
OS	macOS Version 12.6 (Build 21G115)

• Verified steps from issue description and brave/brave-core#14817
• Verified there is smooth scroll on deposit screen
• Verified smooth scroll on portfolio with tokens and NFT's