Fix density plot error by using correct bandwidth string in BuildPlots.R

[AtomChen0425]

Summary

This PR fixes a bug in BuildPlots.R where the use of an incorrect bandwidth string in geom_density() caused runtime errors when generating density plots.

Changes

• Replaced bw = "SJ" with bw = "sj" in all geom_density() calls:
  • Line 108
  • Line 121
  • Line 158

Problem

The original code used bw = "SJ" (uppercase), which is not a valid option for the bw parameter in geom_density(). This caused the following error:

2: Computation failed in `stat_density()`.
Caused by error in `precompute_bw()`:
! `bw` must be one of "nrd0", "nrd", "ucv", "bcv", "sj", "sj-ste", or
  "sj-dpi", not "SJ".
ℹ Did you mean "sj"? 
3: Computation failed in `stat_density()`.
Caused by error in `precompute_bw()`:
! `bw` must be one of "nrd0", "nrd", "ucv", "bcv", "sj", "sj-ste", or
  "sj-dpi", not "SJ".
ℹ Did you mean "sj"? 
4: Computation failed in `stat_density()`.
Caused by error in `precompute_bw()`:
! `bw` must be one of "nrd0", "nrd", "ucv", "bcv", "sj", "sj-ste", or
  "sj-dpi", not "SJ".
ℹ Did you mean "sj"? 
5: Computation failed in `stat_density()`.
Caused by error in `precompute_bw()`:
! `bw` must be one of "nrd0", "nrd", "ucv", "bcv", "sj", "sj-ste", or
  "sj-dpi", not "SJ".
ℹ Did you mean "sj"? 
6: Computation failed in `stat_density()`.
Caused by error in `precompute_bw()`:
! `bw` must be one of "nrd0", "nrd", "ucv", "bcv", "sj", "sj-ste", or
  "sj-dpi", not "SJ".
ℹ Did you mean "sj"? 

Fix

Changed the bandwidth method to lowercase "sj", which is a valid and robust choice for density estimation.

Impact

This fix ensures that density plots are generated correctly without runtime errors, improving the reliability of the plotting templates.

[AndreyAkinshin]

@AtomChen0425 thanks!