All Linux microbenchmark runs failed with "ModuleNotFoundError: No module named 'helix'" at the end of the run

Al the Linux microbenchmark runs failed with the follow error. Looks like PYTHONPATH= is not set [here](https://github.com/dotnet/runtime/blob/57bfe474518ab5b7cfe6bf7424a79ce3af9d6657/eng/testing/performance/microbenchmarks.proj#L35)
+ export _commandExitCode=0
+ /usr/bin/python3 /home/helixbot/work/B1FC095A/p/reporter/run.py https://dev.azure.com/dnceng/ internal 38302850 eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6Im9PdmN6NU1fN3AtSGpJS2xGWHo5M3VfVjBabyJ9.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.FW1gw46gdprwxVvytqqdhkCh0rGItKE0mDX_IWfHRSnCnZM82T-6zkksE746usYBAaM4BlDqSiWhlpgcdSLGoR9HFa-UGwkA0AaK2OSvbvTbyyu_fBQLeeiVDGHMlH9k1mKXIuZS_14ZL8QqqCLETANVv2FJ-vNbojjIdrIbqZYjRvyfTWXBQfsV0orbvU_UCU12V5ijilo-TaqU0XIwLPXMZ-yxA2wq3yjYEb2iexnazb6qcgfshUzfGiFYSf55y5aDymNsT8rUyStJ5Wlzl0xUF7qnq86hc_sD3DLMdL-ojYf_odOYwhP_1liXEezwpItGKG907Y_LAapE8s4IGA
Traceback (most recent call last):
File "/home/helixbot/work/B1FC095A/p/reporter/run.py", line 13, in
from test_results_reader import read_results
File "/home/helixbot/work/B1FC095A/p/reporter/test_results_reader/__init__.py", line 3, in
from helix.public import TestResult, TestResultAttachment
ModuleNotFoundError: No module named 'helix'