Update input data for metrics

[ambrosejcarr]

There are several tests (marked with todo in test_metrics.py which are not adequately tested because the metadata contains no examples of what they measure.

For example:

• multi-aligned reads
• incorrect cell barcodes
• reads mapping to UTR or intronic regions
• multi-mapping reads

There are several metrics which were inconsistent with notebook versions:

• molecule_barcode_fraction_bases_above_30_variance
• reads_per_molecule
• fragments_per_molecule
• cell metrics fragments_with_single_read_evidence
• cell metrics molecules_with_single_read_evidence