Get rid of meta2 in run_alphafold2_pred

### Description of feature

The `meta2` [here](https://github.com/nf-core/proteinfold/blob/a8e587a874db1a8af9e82ad6fefbb57ce0a98fb2/modules/local/run_alphafold2_pred/main.nf#L25) contains the same as the `meta` above. Hence, we can get rid of it and provide an input channel that includes both `fasta` and `features`.