Incorrect text ("invite code") on join screen

[holmesworcester]

Right now the join screen says "invite code" instead of "invite link", which is confusing to users because we don't offer invite codes anymore. This just came up in a demo and it's a tiny change, so I'm adding it to the next sprint.

It should say "invite link" instead of "invite code", both in the text above the from field and in the placeholder text in the field itself.

Here's the screen:

[EmiM]

Technically we accept both link and the code (so only params part of the link). But yeah, it's more likely that user will use the whole link.