Ensure that Azure managed disks are consistent across pools

[rak-phillip]

Summary

This helps to avoid errors that can occur when mixing non-managed availability sets and managed availability sets in an azure cluster.

Fixes #16288

Occurred changes and/or fixed issues

• Override default pool value to match base pool
• Confirm when the user that they want to update Managed Disks for all pools if more than one pool exists

Technical notes summary

This change makes some assumptions about how to work with managed disks in azure clusters:

1. The value for managed disks must be the same across all pools
2. If 1 is true, the "base" pool controls the default managed disks value when adding new pools

Areas or cases that should be tested

See the issue for more details.

1. Creating a new Azure rke2 cluster
   2. Change the default value for managed disks
   3. Add a new pool and assert that the default value matches the existing pool
2. Editing an Azure rke2 cluster
   3. Add a new pool and assert that the default value matches the existing pool
   4. Attempt to modify the value for the new pool. A modal with raise asking the user to confirm that they want to update all pools

Areas which could experience regressions

This will fail validation if there are valid scenarios where pools can mix managed disks.

Screenshot/Video

2026-01-07.12-20-47.mp4

Checklist

• The PR is linked to an issue and the linked issue has a Milestone, or no issue is needed
• The PR has a Milestone
• The PR template has been filled out
• The PR has been self reviewed
• The PR has a reviewer assigned
• The PR has automated tests or clear instructions for manual tests and the linked issue has appropriate QA labels, or tests are not needed
• The PR has reviewed with UX and tested in light and dark mode, or there are no UX changes
• The PR has been reviewed in terms of Accessibility
• The PR has considered, and if applicable tested with, the three Global Roles Admin, Standard User and User Base

[rak-phillip]

I had an oob discussion with @oboc-sts to review the validation implementation. We arrived at the conclusion that the preferred approach is to implement a pattern that will keep the pools in sync for the user. We will accomplish this by:

• adding an informational tooltip that explains how this values needs to be the same for all pools to the managed disks checkbox
• adding a modal for the user to confirm taking action on updating all of the pools if managed disks changes

[rak-phillip]

Converting to draft as we gather more details on the implementation: #16288 (comment)