test(e2e+machine): Base structure for machine mode testing within E2E for oss

[charliedmcb]

Fixes #

Description
Adding the base structure for E2E testing using machine mode for oss.

• Framework changs from this PR:
  DO-NOT-MERGE: Staging testing ground for E2E work, on top of Machine API POC branch #1204

Creates a BYO nodepool, and adapts the mode setting from here:

• https://github.com/Azure/karpenter-provider-azure/pull/1199/files
  • Does still need to handle the case for old expect statements not working for machine mode

How was this change tested?

E2E runs

scriptless:

• https://github.com/Azure/karpenter-provider-azure/actions/runs/18389347689
• https://github.com/Azure/karpenter-provider-azure/actions/runs/18397924767

aksmachineapi:

• https://github.com/Azure/karpenter-provider-azure/actions/runs/18389364777
• https://github.com/Azure/karpenter-provider-azure/actions/runs/18397941620

Does this change impact docs?

• Yes, PR includes docs updates
• Yes, issue opened: #
• No

Release Note

NONE