Handle expired invites & fix test registration (#73)

This PR addresses a bridge crash discovered while backfilling old channels, alongside a wee QoL fix for the test suite.

* **Expired Events (`d2m`):** Wraps Discord scheduled event/invite link lookups in a try-catch block. If a link is expired (404 or Discord error 10006), the bridge now posts a fallback `m.notice` rather than throwing an error and halting message conversion.
* **Test Suite Setup:** Updates `test.js` to initialize the mock registration object using `getTemplateRegistration()` preventing test runner crashes when running without a local `registration.yaml` file.

Co-authored-by: Cadence Ember <cadence@disroot.org>
Reviewed-on: https://gitdab.com/cadence/out-of-your-element/pulls/73
Co-authored-by: Bea <beanie@theargo.space>
Co-committed-by: Bea <beanie@theargo.space>

src/d2m/converters/message-to-event.js

@@ -770,7 +770,18 @@ async function messageToEvent(message, guild, options = {}, di) {
 	// Then scheduled events
 	if (message.content && di?.snow) {
 		for (const match of [...message.content.matchAll(/discord\.gg\/([A-Za-z0-9]+)\?event=([0-9]{18,})/g)]) { // snowflake has minimum 18 because the events feature is at least that old
-			const invite = await di.snow.invite.getInvite(match[1], {guild_scheduled_event_id: match[2]})
+			let invite
+			try {
+				invite = await di.snow.invite.getInvite(match[1], {guild_scheduled_event_id: match[2]})
+			} catch (e) {
+				// Skip expired/invalid invites and events
+				if (e.message === `{"message": "Unknown Invite", "code": 10006}`) {
+					break
+				} else {
+					throw e
+				}
+			}
+
 			const event = invite.guild_scheduled_event
 			if (!event) continue // the event ID provided was not valid