More robustly parse metaphlan profile

[alienzj]

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Description

If meet #, humann should just parse next line.

Related Issue

If metaphlan profile contain the line like below:

#mpa_v30_CHOCOPhlAn_201901
#metaphlan 47-H.rmhost.1.fq.gz,47-H.rmhost.2.fq.gz --input_type fastq --ignore_markers s__Ruminococcus_obeum_CAG_39.markers.txt -t rel_ab_w_read_stats --unknown_estimation --add_viruses --output_file profile.tsv --sample_id 47-H
#SampleID       47-H

It will report error:

Traceback (most recent call last):                                                                                                                                   
  File "/home/zhujie/.conda/envs/bioenv3.9/bin/humann", line 10, in <module>                                                                                         
    sys.exit(main())                                                                                                                                                 
  File "/home/zhujie/.conda/envs/bioenv3.9/lib/python3.9/site-packages/humann/humann.py", line 975, in main                                                          
    custom_database = prescreen.create_custom_database(config.nucleotide_database, bug_file)                                                                         
  File "/home/zhujie/.conda/envs/bioenv3.9/lib/python3.9/site-packages/humann/search/prescreen.py", line 102, in create_custom_database
    read_percent=float(data[-2])
IndexError: list index out of range

Screenshots (if appropriate):