fix(infrastructure): remove duplicate tsconfig properties

[moog16]

• strictNullChecks is set to true in strict = true, which is set in gts/tsconfig-google.json
• forceConsistentCasingInFileNames is set to true in gts/tsconfig-google.json

for reference
https://github.com/google/gts/blob/master/tsconfig-google.json

[codecov-io]

Codecov Report

Merging #736 into rc0.11.0 will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           rc0.11.0     #736   +/-   ##
=========================================
  Coverage     95.16%   95.16%           
=========================================
  Files            73       73           
  Lines          2914     2914           
  Branches        442      442           
=========================================
  Hits           2773     2773           
  Misses           46       46           
  Partials         95       95

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