test(NODE-5218): use debug branch from csfle

Author: durran

.evergreen/run-custom-csfle-tests.sh

@@ -27,7 +27,7 @@ ABS_PATH_TO_PATCH=$(pwd)
 # Environment Variables:
 # CSFLE_GIT_REF - set the git reference to checkout for a custom CSFLE version
 # CDRIVER_GIT_REF - set the git reference to checkout for a custom CDRIVER version (this is for libbson)
-CSFLE_GIT_REF=${CSFLE_GIT_REF:-master}
+CSFLE_GIT_REF=${CSFLE_GIT_REF:-NODE-5218}
 CDRIVER_GIT_REF=${CDRIVER_GIT_REF:-1.17.6}
 
 rm -rf ../csfle-deps-tmp