Update channel rooms to be ephemeral

Remove redundant live kit initialization code
Fix bug in recent channel links changes where channel rooms would have the incorrect release set

co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>
co-authored-by: Max <max@zed.dev>

crates/collab/migrations.sqlite/20221109000000_test_schema.sql

@@ -40,6 +40,7 @@ CREATE TABLE "rooms" (
     "release_channel" VARCHAR,
     "channel_id" INTEGER REFERENCES channels (id) ON DELETE CASCADE
 );
+CREATE UNIQUE INDEX "index_rooms_on_channel_id" ON "rooms" ("channel_id");
 
 CREATE TABLE "projects" (
     "id" INTEGER PRIMARY KEY AUTOINCREMENT,