Fix bandgap_tol and delete bandgap_override on MPMetaGGARelaxSetGenerator

[janosh]

Closes #552.

ead2dbc add BANDGAP_TOL: float = 1e-4 to Atomate2Settings
fd0109b test ValidationError on Atomate2Settings with invalid VASP_CMD and BANDGAP_TOL
606af2b delete unused bandgap_override parameter
a329639 VaspInputGenerator pass getattr(self, "bandgap_tol", SETTINGS.BANDGAP_TOL) to _set_kspacing
1b176d1 test passing bandgap_tol to MPMetaGGARelaxSetGenerator in tests/vasp/flows/test_mp.py
a9deeef test ALL incar tags in tests/vasp/flows/test_mp.py

[janosh]

test_empty_and_invalid_config_file is passing locally so the failure here is probably a pydantic 1 vs 2 incompatibility. Let's get #548 merged soon!

[codecov]

Codecov Report

Merging #553 (048daba) into main (5bf473a) will not change coverage.
The diff coverage is 50.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #553   +/-   ##
=======================================
  Coverage   75.62%   75.62%           
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  Files          80       80           
  Lines        6736     6736           
  Branches      999      999           
=======================================
  Hits         5094     5094           
  Misses       1333     1333           
  Partials      309      309           

Files	Coverage Δ
src/atomate2/settings.py	100.00% <100.00%> (ø)
src/atomate2/vasp/sets/mp.py	92.68% <ø> (-0.18%)	⬇️
src/atomate2/vasp/sets/base.py	73.63% <0.00%> (ø)