tests: expect warning on azure pro images. avoid client.destroy

[blackboxsw]

Fix integration test errors seen on Azure UbuntuPro testing seen during SRU review of 26.1

1. Ignore intermittent warning seen on Azure Pro images during first attempt to contact IMDS during first boot.
2. Avoid client.destroy when our integration test is within cloud_session.launch context manager because that teardown is performed by the context manager

Proposed Commit Message

tests: expect warning on azure pro images. avoid client.destroy
    
Avoid client.destroy within the cloud_session.launch context manager
as it already performs cloud.destroy on exit which calls
instance.destroy. This avoids the following error seen by pycloudlib
on Azure instances:
    
  <pycloudlib.azure.instance.AzureInstance object at ....
    
  @property
   def id(self):
      """Return instance id."""
       return self._instance["vm"].id
              ^^^^^^^^^^^^^^^^^^^^
   E     TypeError: 'NoneType' object is not subscriptable

Additional Context

Test Steps

Merge type

• Squash merge using "Proposed Commit Message"
• Rebase and merge unique commits. Requires commit messages per-commit each referencing the pull request number (#<PR_NUM>)

[holmanb]

GitHub can't show me the files currently, but from the description I don't see how this is a pro-specific issue. Can you please elaborate?