bug: pubsubTopic and contentTopics are required for store v3 requests

[fbarbu15]

Describe the bug
Raising this as a bug because on nwaku those 2 fields are not required in the store v3 requests
Also the schema doesn't show those fields as mandatory

To Reproduce

1. Send a request with only pubsubTopic to retrieve all the messages in the store for that pubsubTopic

Actual behavior
{"status_code":400,"status_desc":"pubsubTopic and contentTopics are required"}

Expected behavior
Should work IMO

go-waku version/commit hash

harbor.status.im/wakuorg/go-waku:latest