Disable View page source on chrome-extension pages

[Sh1d0w]

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).

Fixes #4812

Auditors:
@bbondy

[luixxiul]

Rather I'm thinking that the common context menu itself on about pages should be disabled.

[Sh1d0w]

@luixxiul Ok I am closing the PR. I read in the original issue you have opened you wanted the element eighter hidden or grayed out ... :)

[luixxiul]

yes sorry @Sh1d0w still you don't have to close the issue as it was not decided to disable it. Also in this case other elements should be grayed out too like 1Password, reload page, etc, while Find, print, bookmark page would be useful here.

[Sh1d0w]

@luixxiul I have removed Reload, Back, Forward, View Source, Inspect element and 1Password entries if you are on extension page. Can you please confirm the behaviour is correct like this? Thanks

[bbondy]

We should only disable the things which do not work, can you confirm if that's the case in the PR?
Do any of these work?

Also in this case other elements should be grayed out too like 1Password, reload page, etc, while Find, print, bookmark page would be useful here.

[Sh1d0w]

@luixxiul Can you confirm the items I have removed are ones that do not work?

[luixxiul]

These do not work

• Password manager (1Password etc)
• Reload page
• View Page Source

These work

• Back
• Forward
• Find
• Print
• Bookmark page
• Inspect Element

[Sh1d0w]

@bbondy The PR is updated. Let me know if I have to amend anything else.

[bbondy]

What doesn't work about extension pages and reload? I'm wondering because our pdf viewing is done without reloading. Are you sure it doesn't work?

[bbondy]

It seems like it should

[bsclifton]

Closing this PR in favor of #5559 which disables context menu items ONLY on the about pages.

Apologies that we didn't communicate more about this one ☹️ This PR probably should have only solved the about pages, unless there is an existing issue for the other work