fix(pandas list): deal with cellids with inconsistent types

[scottrp]

No description provided.

[codecov]

Codecov Report

Merging #1980 (a235330) into develop (1eddf86) will decrease coverage by 0.1%.
Report is 1 commits behind head on develop.
The diff coverage is 76.2%.

@@            Coverage Diff            @@
##           develop   #1980     +/-   ##
=========================================
- Coverage     72.7%   72.7%   -0.1%     
=========================================
  Files          257     258      +1     
  Lines        57809   58827   +1018     
=========================================
+ Hits         42074   42788    +714     
- Misses       15735   16039    +304     

Files	Coverage Δ
flopy/mf6/data/mfdata.py	75.8% <100.0%> (+0.1%)	⬆️
flopy/mf6/data/mfdataarray.py	60.9% <ø> (-0.1%)	⬇️
flopy/mf6/data/mfdatalist.py	64.4% <100.0%> (-7.0%)	⬇️
flopy/mf6/data/mfdatascalar.py	60.5% <ø> (-0.2%)	⬇️
flopy/mf6/mfsimbase.py	67.5% <100.0%> (+<0.1%)	⬆️
flopy/mf6/modflow/mfgwfchd.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwfdrn.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwfevt.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwfevta.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwfghb.py	100.0% <ø> (ø)
... and 17 more

... and 2 files with indirect coverage changes