fix(controller): Optimize logic for detach VG from VM for cases with large number of VGs

[thunderboltsid]

We optimize the logic and add some guardrails

• Add a timeout on the context for polling
• Increase the polling interval to 5s
• Set immediate polling to false to reduce likelihood of a 404 on tasks
• Call detachVG one after the other and build a list of tasks
• wait for all tasks in the list to reach a terminal state

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 7.14286% with 13 lines in your changes missing coverage. Please review.

Project coverage is 33.00%. Comparing base (5d63d09) to head (69f7b5b). Report is 1 commits behind head on main.

Files	Patch %	Lines
controllers/nutanixmachine_controller.go	12.50%	7 Missing :warning:
controllers/helpers.go	0.00%	6 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #477 +/- ## ========================================== + Coverage 32.56% 33.00% +0.43% ========================================== Files 17 17 Lines 1833 1809 -24 ========================================== Hits 597 597 + Misses 1216 1192 -24 Partials 20 20 ```

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