Rename livekit_server to livekit_api (#24984)

The name `livekit_server` was a bit misleading as it is not a server and
gets built into both the client and server - the server code is in
`collab`.

Release Notes:

- N/A

crates/collab/Cargo.toml

@@ -40,7 +40,7 @@ google_ai.workspace = true
 hex.workspace = true
 http_client.workspace = true
 jsonwebtoken.workspace = true
-livekit_server.workspace = true
+livekit_api.workspace = true
 log.workspace = true
 nanoid.workspace = true
 open_ai.workspace = true