extension forces context menu container settings

[R-Chandra]

When this extension is enabled in Firefox, it forces privacy.userContext.enabled and privacy.userContext.ui.enabled to true. I did not expect any addons to force these settings. I don't like this being inserted into the context menu, so I set both of these to false. But as soon as I enable this extension, these both get forced to true, thus showing the context menu item again. If the user disables this (e.g., in about:config or user.js), this shouldn't force it back on.