QC report aesthetic updates

[sjspielman]

Closes #618 Closes #620

This PR makes two viz changes to the QC report:

• For #620, I updated the miQC plot line thickness as described in the isssue
• For #618, I updated the UMAP point size. I explored a variety of different numbers of cells and tweaked numbers accordingly. In the attached zip here, I include a bunch of reports where the file name contains the number of cells. All these reports include the update miQC line sizing, too.
  • Once we agree on the point sizes, I will port the code defining the umap point sizes into the cell type supplemental report. I feel like we might want to put that in a function for Future Us, which might entail making a new utils/report_functions.rmd file? Thoughts?

Let me know what you think of sizing choices!

qc_reports_cell_counts.zip

[sjspielman]

I played around with a couple different SCEs looking at a 2000 vs 2500 cutoff, and honestly it all looked fairly similar to me so i went with a 2250 cutoff 😂 . I wrote this up into a function in a new utils file which is now "sourced" in both the main and supplemental cell type report.