fix(data check): Minimum number of data columns check fixed (#1062)

[spaulins-usgs]

Minimum number of data columns was not being calculated correctly for columns that can either repeat and be zero. Replaced old calculation of minimum data columns with updated calculation based on the code that builds the column headers.

[codecov]

Codecov Report

Merging #1065 (20b8753) into develop (8a2cffb) will increase coverage by 0.983%.
The diff coverage is 87.500%.

@@              Coverage Diff              @@
##           develop     #1065       +/-   ##
=============================================
+ Coverage   71.761%   72.745%   +0.983%     
=============================================
  Files          225       221        -4     
  Lines        51891     51143      -748     
=============================================
- Hits         37238     37204       -34     
+ Misses       14653     13939      -714     

Impacted Files	Coverage Δ
flopy/mf6/modflow/mfgnc.py	32.142% <ø> (ø)
flopy/mf6/modflow/mfgwf.py	55.555% <ø> (ø)
flopy/mf6/modflow/mfgwfbuy.py	58.064% <ø> (ø)
flopy/mf6/modflow/mfgwfchd.py	56.521% <ø> (ø)
flopy/mf6/modflow/mfgwfcsub.py	53.781% <ø> (ø)
flopy/mf6/modflow/mfgwfdis.py	62.222% <ø> (ø)
flopy/mf6/modflow/mfgwfdisu.py	59.154% <ø> (ø)
flopy/mf6/modflow/mfgwfdisv.py	59.574% <ø> (ø)
flopy/mf6/modflow/mfgwfdrn.py	56.000% <ø> (ø)
flopy/mf6/modflow/mfgwfevt.py	55.769% <ø> (ø)
... and 67 more