Bug: adlsgen2setup.py does not use $AZURE_ADLS_GEN2_FILESYSTEM env var

[cforce]

azure-search-openai-demo/scripts/adlsgen2setup.py

Line 169 in 023dc1b

filesystem_name="gptkbcontainer",

This shall be
filesystem_name=os.environ["AZURE_ADLS_GEN2_FILESYSTEM"],

[cforce]

see #2111