Fix invalid escape sequence in EMR test

[aemous]

Notes:

• This change fixes GH CI test errors in v2. We do not see this errors in v1, because v2 is specifically configured to treat DeprecationWarnings as errors, which is not the case for v1. This PR is still worth creating to resolve the warning in v1.

Description of changes:

• v1 port of Fix failing EMR customization unit test #9865

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.34%. Comparing base (68039fa) to head (b51dee0).
⚠️ Report is 406 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #9866      +/-   ##
===========================================
- Coverage    93.40%   93.34%   -0.06%     
===========================================
  Files          211      209       -2     
  Lines        17012    16827     -185     
===========================================
- Hits         15890    15708     -182     
+ Misses        1122     1119       -3     

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