cannot use free query auth to query deployments without allocations

[Theodus]

The scenario is as follows:

• the indexer is indexing the network subgraph deployment
• the indexer does not have an active allocation for the network subgraph
• attempts to query the indexer-service for the network subgraph deployment, using the free query auth token, fails because there is no allocation signer for the deployment.

I think the indexer-service should be able to handle requests using free query auth without producing an attestation. This was possible in prior versions.

[Theodus]

resolved by #622