Channel decoder should (optionally) return CRC status

[catkira]

As discussed in this PR, it would be nice if the decoder functions return the CRC status (ok or failed). Sebastian suggested to add an extra flag return_crc_status to the decoder routine to enable the CRC status output optionally. Should I make a PR for this or is somebody else already on it?

[SebastianCa]

We plan to integrate this feature in the next release of Sionna. There is no need for an additional PR.