{AKS} Refactor aks nodepool update - part 2

[FumingZhang]

Description

• Refactor upgrade settings
• Refactor mode, scale_down_mode

Unit Test Coverage

• "covered_lines": 578,
• "num_statements": 578,
• "percent_covered": 100.0,
• "percent_covered_display": "100",
• "missing_lines": 0,
• "excluded_lines": 0

Testing Guide

History Notes

[Component Name 1] BREAKING CHANGE: az command a: Make some customer-facing breaking change
[Component Name 2] az command b: Add some customer-facing feature

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[yonzhan]

AKS