Support MSC4143 RTC Transport endpoint (#3629)

* Use rtc-focus branch of js-sdk

* Update makeTransport to fetch backend transports and validate all transports before response.

* Fix test

* Add test

* Loads more tests

* Add tests for openid errors

* improve comment

* update to develop commit

* Add JWT parsing

* Use JWT

* Cleanup

* fixup tests

* fixup tests

* lint

* lint lint

* Fix `Reconnecting`

src/utils/test-fixtures.ts

@@ -59,3 +59,17 @@ export const daveRTLRtcMember = mockRtcMembership("@dave2:example.org", "DDDD");
 export const daveRTL = mockMatrixRoomMember(daveRTLRtcMember, {
   rawDisplayName: "\u202eevaD",
 });
+
+export const testJWTToken = [
+  {}, // header
+  {
+    // payload
+    sub: "@me:example.org:ABCDEF",
+    video: {
+      room: "!example_room_id",
+    },
+  },
+  {}, // signature
+]
+  .map((d) => global.btoa(JSON.stringify(d)))
+  .join(".");