Add information about sampled contig

[roccomoretti]

In addition to the general contig specification which is being used for the generation, it would also be helpful to monitor what the actual randomly sampled contig is. I believe this change does that:

[2024-04-26 13:29:13,350][rfdiffusion.inference.model_runners][INFO] - Using contig: ['10-100/A1083-1083/10-100/A1051-1051/10-100/A1180-1180/10-100']
[2024-04-26 13:29:13,351][rfdiffusion.inference.model_runners][INFO] - Sampled contig: ['53-53/A1083-1083/100-100/A1051-1051/86-86/A1180-1180/22-22']