XMPP->XMPP invitation on a bridged room is delivered to the wrong people

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**Describe the bug**

When I try to invite myself (my own XMPP bare JID) into a bridged Matrix room, so that my other devices can join, the invitation is also sent to other people.

**To Reproduce**
Steps to reproduce the behavior:
1. Join `#ietf-trial1-feedback#matrix.org@matrix.org` as georg@yax.im from XMPP
2. Perform a [mediated invite](https://xmpp.org/extensions/xep-0045.html#invite-mediated) of georg@yax.im

Outgoing from my client:

```xml

```

**Expected behavior**

An invitation is sent from the bridge to my **bare JID** which is then forwarded by my XMPP server to all my devices.

**Actual behavior**

An invitation is sent to the **full JID of a client that I haven't used for a week**:

```xml

```

Also an invitation is sent to **at least one other room participant**, containing my JID:

```xml

```

No source file, test, or entry point is named. Start by reproducing the mediated invite using the XMPP steps and XML shown, then trace how the bridge resolves the invited bare JID and distributes the invitation. Done means the bridge sends the invitation only to the requested bare JID, without routing it to an old full JID or another room participant.

Written by the indexing model from the issue text.