Add Filecoin to onboarding onramp assets for purchase

[josheleonard]

Description

Filecoin was not show as a purchasable currency during onboarding.

Steps to Reproduce

1. Create a wallet
2. Navigate to brave://wallet/crypto/fund-wallet
3. Attempt to purchase FIL

Actual result:

FIL is not shown in the list

Expected result:

FIL is show in the list or purchasable assets

Reproduces how often:

Easy

Brave version (brave://version info)

1.44.101 Chromium: 106.0.5249.65 (Official Build) (arm64)

Version/Channel Information:

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

[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 steps from issue description and brave/brave-core#15250
• Verified Filecoin is listed and able to purche via onramp provider

25660.mp4

---

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 steps from issue description and brave/brave-core#15250
• Verified Filecoin is listed and able to purche via onramp provider

25660.mp4

---

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 13.0 (Build 22A380)

• Verified steps from issue description and brave/brave-core#15250
• Verified Filecoin is listed and able to purche via onramp provider

25660.mov