fix(network-subgraphs): [ETH-876] limit the length of Stream entity id field

[jtakalai]

Changes

If streamId is too long, cut and use hash (for uniqueness). Currently no streams have such long IDs, so for existing clients, this change is transparent.

minor cleanup: let -> const

Why

Overlong ID could break the subgraph indexing

Future work

This provides a simple upgrade path for SDK: instead of querying Stream.id, query Stream.streamId (which as an added bonus is of type String and not ID so can be queried with "contains")

[linear]

ETH-876 Long Stream.id can break The Graph

[teogeb]

My suggestion is that we limit the length of the stream ID in StreamRegistry#createStream. If I understood correctly, there is no need for overlong stream ids in practice. The approach in this PR adds significant amount of complexity and confusion as "Stream#id" field in The Graph is no longer same as Stream's ID.

[jtakalai]

My suggestion is that we limit the length of the stream ID in StreamRegistry#createStream.

It's an option that requires a change to the StreamRegistry contract. The current PR works as a subgraph update. Of course it can still be changed later with minimal hassle.

The complexity added here isn't very significant, and confusion can be remedied with documentation.