bug: duplicate validator for topic error when trying to re-subscribe to previously unsubscribed topic

[fbarbu15]

To Reproduce
Steps to reproduce the behavior:
Using REST API or RPC:

1. Subscribe to a topic
2. Un-Subscribe from that topic
3. Re-Subscribe back to that topic
   => HTTP 500 with empty response on REST
   => HTTP 400 with duplicate validator for topic on RPC

Error can also be seen in the attached docker log
node1_2023-11-23_09-46-33__2aa529bb-3b7b-47f3-8454-de0f18123539__wakuorg_go-wakulatest.log

Expected behavior
This should work, it works on nwaku side. Seems that some cleanup is not done correctly when unsubscribing

go-waku version/commit hash

wakuorg/go-waku:latest

[chaitanyaprem]

Weekly Update

• achieved: fix relay subscribe API issue causing failure in resubscription to a pubsubtopic, return appropriate errors in relay REST API