removing "Mobile Sync" from "Settings -> Advanced"

[kjozwiak]

Description

We should remove the Sync with Mobile feature/setting from Settings -> Advanced via brave://wallet as per https://github.com/brave/ethereum-remote-client/wiki/Testing, specifically the following:

Under the advanced tab, there should be no prompt for Mobile Sync

Steps to Reproduce

1. open brave and create a crypto wallet via brave://wallet
2. once you've created the wallet, click on the profile avatar and select Settings -> Advanced and you'll notice that Sync with Mobile is available

Actual result:

Expected result:

We should remove Sync with Mobile from Settings -> Advanced as per https://github.com/brave/ethereum-remote-client/wiki/Testing, specifically the following:

Under the advanced tab, there should be no prompt for Mobile Sync

Reproduces how often:

100% reproducible using the STR mentioned above.

Brave version (brave://version info)

Brave	0.69.131 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	macOS Version 10.14.6 (Build 18G95)

Version/Channel Information:

• Can you reproduce this issue with the current release? N/A (not released)
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the dev channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Does the issue resolve itself when disabling Brave Rewards? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Miscellaneous Information:

CCing @ryanml @bbondy @tomlowenthal @rebron @brave/legacy_qa

[kjozwiak]

@bbondy not sure if the above should be removed, but https://github.com/brave/ethereum-remote-client/wiki/Testing, specifically the following sounded like Sync with Mobile should be removed:

Under the advanced tab, there should be no prompt for Mobile Sync

[bbondy]

I think this is fixed with the latest ethereum-remote-client extension update

[srirambv]

Verification passed on

Brave	0.69.131 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	Windows 10 OS Version 1903 (Build 18362.30)

• Verified Mobile Sync section is removed from advanced settings for component 1.0.9
  

Verification passed on

Brave	0.69.131 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	Linux

• Verified Mobile Sync section is removed from advanced settings for component 1.0.9
  

Verification PASSED on macOS 10.14.6 x64 using the following build:

Brave	0.69.131 Chromium: 77.0.3865.90 (Official Build) (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	macOS Version 10.14.6 (Build 18G95)

• ensured that Sync with Mobile was removed from Settings -> Advanced using Crypto Wallets - Version: 1.0.9