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 about single retry seen on some Azure Pro images during first attempt to contact IMDS during first boot. This issue seems to occur most frequently on Azure marketplace Pro images but may not be limited to Pro images.

2. Avoid client.destroy when our integration test is within cloud_session.launch context manager because that tear down is performed by the context manager.

Proposed Commit Message

tests: expect intermittent warning accessing Azure IMDS. Avoid client.destroy

Avoid client.destroy within the cloud_session.launch context manager
as it already performs cloud.destroy on context 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
               ^^^^^^^^^^^^^^^^^^^^
      TypeError: 'NoneType' object is not subscriptable

Additionally, some Azure instance launches encounter intemittent
warning reaching IMDS on first attempt. Avoid failing integration
tests when encountering a single warning about IMDS access.

If multiple retries are required to reach Azure IMDS, treat this as
an error.

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?