Binance Widget should be disconnected after hiding

[ryanml]

Description

When hiding the Binance Widget via settings/widget menu, we should revoke the access token and reset the widget.

Steps to Reproduce

1. Connect via Oauth on the Binance widget.
2. Using the ellipsis menu, click "hide"
3. Unhide the widget via footer dashboard settings

Actual result:

Widget State is retained

Expected result:

User should be disconnected with state reset.

Reproduces how often:

100%

Brave version (brave://version info)

Version/Channel Information:

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

Other Additional Information:

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

Miscellaneous Information:

[srirambv]

Verification passed on

Brave	1.9.36 Chromium: 81.0.4044.113 (Official Build) nightly (64-bit)
Revision	cf9d66371ea608e227eed56ccba3abc2701bd23d-refs/branch-heads/4044@{#936}
OS	Windows 10 OS Version 1909 (Build 18363.778)

• Verified hiding the widget disconnects state and reset
• Verified hiding via dashboard or via widget menu resets the connected state

---

Verification passed on

Brave	1.9.36 Chromium: 81.0.4044.113 (Official Build) nightly (64-bit)
Revision	cf9d66371ea608e227eed56ccba3abc2701bd23d-refs/branch-heads/4044@{#936}
OS	Linux

• Verified hiding the widget disconnects state and reset
• Verified hiding via dashboard or via widget menu resets the connected state

---

Verification passed on

Brave	1.9.36 Chromium: 81.0.4044.113 (Official Build) nightly (64-bit)
Revision	cf9d66371ea608e227eed56ccba3abc2701bd23d-refs/branch-heads/4044@{#936}
OS	macOS Version 10.15.4 (Build 19E287)

• Verified hiding the widget disconnects state and reset
• Verified hiding via dashboard or via widget menu resets the connected state

[jonathansampson]

We should not make a network request unless there is a token to be revoked. For users who just installed Brave, hiding these widgets (without ever having used them) results in a token revocation request being made. These requests do not contain a token, since the user never actually used the widget.