IPFS context menu should be disabled in Private windows

[stephendonner]

Description

Steps to Reproduce

1. install 1.45.41
2. launch Brave
3. load ipns://docs.ipfs.io
4. click on Use a Brave local IPFS node
5. click on the "hamburger menu" -> New Private Window or New Private Window with Tor
6. load search.brave.com
7. context-click the page or the brave logo
8. look at the context menus

Actual result:

IPFS context menu 1	IPFS context menu 2

Expected result:

These don't work. We should remove them, I think, because we remove them in the top-level/"hamburger" menu, for these window types.

Of course, if they're supposed to stay, we should fix them.

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 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:

cc @lidel @cypt4 @diracdeltas

[rebron]

cc: @spylogsster

[vadimstruts]

The IPFS local node and scheme has been deprecated