Improve wallet networks list UX

[supermassive]

From https://bravesoftware.slack.com/archives/C02S9LFEXU4/p1669733487021219

• Maybe just have all testnets shown in list of networks but have the eye (set to hidden) for all of them by default. The disadvantage is you'd have to show each test network individually. The advantage is maybe you don't wall all of them to be seen anyway.
• And get rid of the "show test networks" toggle
• Also let's show a disabled eye icon for default networks with a proper tooltip.
• For portfolio and nft screen network component should list visible test networks in separate bottom section.

[srirambv]

Verification passed on

Brave	1.48.151 Chromium: 109.0.5414.119 (Official Build) beta (64-bit)
Revision	772095164c7d5d4e73160f858efed3b5e87eca83-refs/branch-heads/5414@{#1458}
OS	Linux

• Verified steps from brave/brave-core#16199
• Verified test networks are disabled by default on a clean profile and upgrade profile where it wasn't enabled
• Verified on Portfolio page and NFT page Test networks are listed under its own heading in the network picker
• Verified eye button is always shown on networks setting and also shows tooltip when hovered over

27058.mp4

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Verification passed on

Brave	1.48.151 Chromium: 109.0.5414.119 (Official Build) beta (64-bit)
Revision	772095164c7d5d4e73160f858efed3b5e87eca83-refs/branch-heads/5414@{#1458}
OS	Windows 11 Version 22H2 (Build 22621.755)

• Verified steps from brave/brave-core#16199
• Verified test networks are disabled by default on a clean profile and upgrade profile where it wasn't enabled
• Verified on Portfolio page and NFT page Test networks are listed under its own heading in the network picker
• Verified eye button is always shown on networks setting and also shows tooltip when hovered over

27058.mp4

---

Verification passed on

Brave	1.48.151 Chromium: 109.0.5414.119 (Official Build) beta (arm64)
Revision	772095164c7d5d4e73160f858efed3b5e87eca83-refs/branch-heads/5414@{#1458}
OS	macOS Version 13.0 (Build 22A380)

• Verified steps from brave/brave-core#16199
• Verified test networks are disabled by default on a clean profile and upgrade profile where it wasn't enabled
• Verified on Portfolio page and NFT page Test networks are listed under its own heading in the network picker
• Verified eye button is always shown on networks setting and also shows tooltip when hovered over

27058.mov