ref(metrics): Create extracted metrics summary for sets with min/max/sum of 0

[Dav1dde]

It seems to me that snuba consumer expects those fields and fails when those fields are not present, and the metric summary is than never persisted in the database (metric summary table doesn't allow this fields to be NULL, so I think setting those fields to 0 is the best solution)

Created by Relay:

Sent from the SDK:

PR creates the set summary using the same 0 defaults.

#skip-changelog

[jjbayer]

Should we type these fields to be non-optional, if the consumer cannot handle them otherwise?

[Dav1dde]

According to the Kafka schema, any of these is required. So technically it should work if we just send min: Some(0) but keep the others None ... Unfortunately this is quite hard to express in the typesystem.

[phacops]

The Kafka schema was updated to make min, max, sum optional and make count required 0. Now updating the consumer 1 to support the optional values.

After this, I don't think this PR will be needed anymore.

[Dav1dde]

Thanks Pierre!