Update required on "Inspection of a BAM file" section.

https://github.com/galaxyproject/training-material/blob/53a15dbbd18b01c556eceb16c1e88dafdb9cbc7a/topics/sequence-analysis/tutorials/mapping/tutorial.md?plain=1#L189

Some discrepancies found when delivering a workshop using Mapping Tutorial.

1) Samtools stats (2.0.2+galaxy2).
- Use a reference sequence : Locally cached/Use a built-in genome (on the GTN) vs Locally cached ( correct version )
- Using genome : Mouse (Mus musculus): mm10 Full (on the GTN) vs Mouse (Mus musculus): mm10 ( correct version)

2) The output of the samtools stats before filtering
- The samtools output is not consistent with what's on the GTN.
- ~21,900 mismatches (on the GTN) vs 32663 ( actual output in the report)
- ~4,753,900 bases mapped (on the GTN) vs 5004018 ( actual output in the report)
- ~0.005 mismatches per mapped base (on the GTN) vs 6.527354e-03 ( actual output in the report)

3) The output of the samtools stats after filtering
- Before filtering: 95,412 reads and after filtering: 89,664 reads. (on the GTN)
- Reads mapped : 92152 and read properly paired 90644 ( actual output in the report) ??

Open topics/sequence-analysis/tutorials/mapping/tutorial.md at the linked “Inspection of a BAM file” section and compare its Samtools stats settings and reported outputs with the workshop findings. Check the reference sequence, mm10 selection, and before- and after-filtering values. Done means the tutorial accurately reflects the current results and settings.

Written by the indexing model from the issue text.