chore: update aks tests for 1.9 release

[NohaIhab]

part of #809

Updated the AKS tests workflow to deploy latest/beta when 1.9 release is entered in the input
Here is a sample run, note that:

• We should re-run after Update the UATs dependencies for CKF 1.9 charmed-kubeflow-uats#73 is closed
• Once we cut the branches, we should send another PR to point the 1.9 tests to 1.9/edge and re-run the tests.
• When 1.9/stable is released, we should send a PR to point the tests to 1.9/stable bundle.

Issue should stay open until the above is complete, I will keep track of the above notes in the issue.