[Feature] make it easier to debug issues by providing subgraph hash in http request header to substreams

[matthewdarwin]

Description

When using substreams powered subgraphs, when connecting to the substreams grpc endpoint also provide the subgraph hash via an HTTP request header (eg x-subgraph-hash). This can be logged on the substreams side to improve ability to debug problems.

Are you aware of any blockers that must be resolved before implementing this feature? If so, which? Link to any relevant GitHub issues.

No response

Some information to help us out

• [ ] Tick this box if you plan on implementing this feature yourself.
• [X] I have searched the issue tracker to make sure this issue is not a duplicate.

[azf20]

Thanks @matthewdarwin - @mangas would this be a simple thing to add?

[YaroShkvorets]

PR ready for review: https://github.com/graphprotocol/graph-node/pull/5319