[Test] adding dotenv loading to powershell prep (Azure#19166)

* adding dotenv loading to powershell prep

* moving loaddotenv

Author: seankane-msft

tools/azure-sdk-tools/devtools_testutils/powershell_preparer.py

@@ -9,7 +9,7 @@
 from . import AzureMgmtPreparer
 from .resource_testcase import RESOURCE_GROUP_PARAM
 from azure_devtools.scenario_tests.exceptions import AzureTestError
-
+from dotenv import load_dotenv, find_dotenv
 
 class PowerShellPreparer(AzureMgmtPreparer):
     def __init__(
@@ -56,6 +56,7 @@ def _set_mgmt_settings_real_values(self):
             os.environ["AZURE_CLIENT_SECRET"] = os.environ["{}_CLIENT_SECRET".format(self.directory.upper())]
 
     def create_resource(self, name, **kwargs):
+        load_dotenv(find_dotenv())
 
         if self.is_live:
             self._set_mgmt_settings_real_values()