[digital-carbon] Handle potential sync breakages

[psparacino]

Potential sync issues addressed:

Unsupported registries:

In the past, tokens from the c3 factory have occasionally had registry values not in the Registry enum, which have broken the subgraph sync.

This PR adds a fallback in case c3 issues credits for registries not in the registry enum so there is no break in production. A Debug entity is created when an unsupported registry so the problem can be further assessed and a fix deployed.

handle null values from loadRetire:

loadRetire should never come back null either in practice or by design (therefore it does not follow the load/create pattern). However if a retire comes does back null from this function it will break the sync, as the subgraph will attempt to access a property on null.

This issue has never come up afaik. In the rare event it does this will return before the subgraph attempts to access the property and create a Debug entity.

[0xAurelius]

Isn't adding this entity to production subgraphs going to blow up our entity count?

Or is the logic only going to create one of these when there is an issue with a retirement?

[psparacino]

Isn't adding this entity to production subgraphs going to blow up our entity count?

Or is the logic only going to create one of these when there is an issue with a retirement?

Right; it only creates the Debug entity when an underlying retire isn't found in the RA handleCarbonRetired event (which afaik has never happened) or when there is an unsupported registry (which is rare).