fix: handle invites better

[Asraye]

I'm not entirely sure about this one if It'll be merged; but, here's the list of things!

• No longer tries to handle every rvlt.gg/ as an invite (instead, checks properly.. so wiki.rvlt.gg/ won't be seen as an invite)
• Handles group invites better (rather than just my previous N/A)

Please make sure to check the following tasks before opening and submitting a PR

• I understand and have followed the contribution guide
• I have tested my changes locally and they are working as intended
• These changes do not have any notable side effects on other Revolt projects
• (optional) I have opened a pull request on the translation repository
• I have included screenshots to demonstrate my changes