feat(blobs): revert to constant roots of unity rather than unconstrained

[MirandaWood]

Due to noir-lang/noir#6457, having a huge constants file with the roots of unity is slowing down noir/proving/simulating in the blobs PR (#9302). With this slowdown, proving 3 blobs per block instead of 1 won't run, but 1 isn't enough to contain the fields we expect.

For now, we are calculating the roots of unity in an unconstrained function and using those to move to 3 blobs. This means we are not constraining that we have correctly constructed a blob containing the tx effects of the block, so it's horribly insecure.

Once the above issues are resolve, go back to using the large constants file in noir-projects/noir-protocol-circuits/crates/blob/src/config.nr and delete noir-projects/noir-protocol-circuits/crates/blob/src/unconstrained_config.nr.

[TomAFrench]

The linked issue has been closed, is this still a problem today?