[GOV] Use auth libraries to authenticate in E2E tests

[LizaShak]

Description

As a Azure TRE Developer
I want to eliminate hardcoded login endpoints calls and use azure-identity which we use in other places to authenticate
So that our code is easier to maintain.

Technical notes:

• Replace the REST calls to login.microsoftonline.com
• Consider the following as a replacement: https://learn.microsoft.com/en-us/python/api/azure-identity/azure.identity.clientsecretcredential?view=azure-python and https://learn.microsoft.com/en-us/python/api/azure-identity/azure.identity.usernamepasswordcredential?view=azure-python to replace the manual calls in :
  AzureTRE/e2e_tests/resources/workspace.py and
  AzureTRE/e2e_tests/helpers.py

Acceptance criteria

• e2e run successfully using azure-identity lib to authenticate