fix: use get to avoid key error

[jansenk]

** If the environment doesn't have ENABLE_ORA_PEER_CONFIGURABLE_GRADING defined this line will throw a keyerror

• Note: I don't know why it isn't defined? It looks like it should be? Nevertheless the error is thrown. Investigation for another time.

JIRA: CR-6800

FYI: @openedx/content-aurora

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 95.09%. Comparing base (9359c44) to head (3163fae).
Report is 2 commits behind head on master.

Files	Patch %	Lines
openassessment/xblock/utils/validation.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2213   +/-   ##
=======================================
  Coverage   95.09%   95.09%           
=======================================
  Files         195      195           
  Lines       21479    21479           
  Branches     1931     1931           
=======================================
  Hits        20425    20425           
  Misses        787      787           
  Partials      267      267           

Flag	Coverage Δ
unittests	95.09% <50.00%> (ø)

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[jansenk]

The only failure is codecov. I'm trying to fix an active issue. Not gonna bother with codecov right now

[BrandonHBodine]

lgtm