Support editing network details for Solana and Filecoin

[yrliou]

Mainly for users to be able to customize their block explorer url, and probably JSON RPC URL too. cc @jamesmudgett
We should probably consider have separate sections for EVM, Solana, Filecoin networks in the settings UI with section titles, and only allow user to edit a subset of network fields (such as block_explorer_url, JSON RPC URL) only, things like changing chain_id doesn't make sense in Solana and Filecoin.

[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 brave/brave-core#14879
• Verified Filecoin and Solana networks are listed in their own section
• Verified able to edit existing default networks
• Verified able to reset edit to defaults
• Verified Ethereum defaults works as expected
• Verified Chain ID field is ready only so can't be edited

24569.mp4

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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 brave/brave-core#14879
• Verified Filecoin and Solana networks are listed in their own section
• Verified able to edit existing default networks
• Verified able to reset edit to defaults
• Verified Ethereum defaults works as expected
• Verified Chain ID field is ready only so can't be edited

24569.mp4

---

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 brave/brave-core#14879
• Verified Filecoin and Solana networks are listed in their own section
• Verified able to edit existing default networks
• Verified able to reset edit to defaults
• Verified Ethereum defaults works as expected
• Verified Chain ID field is ready only so can't be edited

24569.mov