Link issues with empty contexts and non-empty identities

[magneticflux-]

A user of a mod I develop reported an issue with CrossTalk that did not manifest in Mumble using the Link plugin. I looked around and did some debugging and found what might be the cause of the issue.

Here's the issue and full debugging steps: https://github.com/magneticflux-/fabric-mumblelink-mod/issues/79#issuecomment-922429042

And here's just the summary:

When sending plugin info, the plugin writes [Ct_None] to a QTextStream if the context is empty (here). Later, when that QTextStream is interpreted (here), the value is taken verbatim, without checking for [Ct_None].
I believe this means that when a client receives info from other clients it sees their contexts incorrectly as "[Ct_None]" but sees its own context correctly as ""?