Update BLOB_SIDECAR_SUBNET_COUNT to 6 in line with max blobs limit update and add it to config

[g11tech]

Since the max blobs limit has been raised, may be subnet count can be bumped too for now

[djrtwo]

agreed

[hwwhww]

If BLOB_SIDECAR_SUBNET_COUNT should always be the same size as MAX_BLOBS_PER_BLOCK, should we just use MAX_BLOBS_PER_BLOCK directly and remove BLOB_SIDECAR_SUBNET_COUNT?

Edited: Also, consider moving it from the "constants" category if it's not a true constant.

[g11tech]

If BLOB_SIDECAR_SUBNET_COUNT should always be the same size as MAX_BLOBS_PER_BLOCK, should we just use MAX_BLOBS_PER_BLOCK directly and remove BLOB_SIDECAR_SUBNET_COUNT?

Edited: Also, consider moving it from the "constants" category if it's not a true constant.

It may be a constant future onwards but may be we can keep it same to begin with

[ppopth]

If BLOB_SIDECAR_SUBNET_COUNT should always be the same size as MAX_BLOBS_PER_BLOCK, should we just use MAX_BLOBS_PER_BLOCK directly and remove BLOB_SIDECAR_SUBNET_COUNT?

Theoretically, they can be different. For example, if the protocol is run in a very high-bandwidth network, MAX_BLOBS_PER_BLOCK can be like 128. While, if BLOB_SIDECAR_SUBNET_COUNT is also 128, the beacon node has to maintain the state for all 128 subnets unnecessarily.

This is analogous to MAX_COMMITTEES_PER_SLOT and ATTESTATION_SUBNET_COUNT. They are both 64.

[hwwhww]

I moved BLOB_SIDECAR_SUBNET_COUNT to the networking config (210c482) as we discussed in the 4844 call today.