Update make generate-openapi to error when API violations occur

[swang392]

What does this PR do?

Updated the make generate-openapi command in Makefile to result in an error when API rule violations are detected.

Motivation

Previously if we make a change to the CRDs that didn't follow the correct formatting to be populated correctly, no error would result when running commands locally (ex: make generate) and warnings wouldn't show up in CI.

Additional Notes

Anything else we should know when reviewing?

Minimum Agent Versions

Are there minimum versions of the Datadog Agent and/or Cluster Agent required?

• Agent: vX.Y.Z
• Cluster Agent: vX.Y.Z

Describe your test plan

tested here: #1626

• remove a field from datadogagent_types.go. Ex: remove a listType, change something from camel case to snake case, remove a description or +optional line.
• run make generate
• Verify that the output contains Error: Warnings detected and the command errored

Checklist

• PR has at least one valid label: bug, enhancement, refactoring, documentation, tooling, and/or dependencies
• PR has a milestone or the qa/skip-qa label

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 48.82%. Comparing base (bc3a576) to head (9df6408).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1627   +/-   ##
=======================================
  Coverage   48.82%   48.82%           
=======================================
  Files         217      217           
  Lines       20874    20874           
=======================================
  Hits        10191    10191           
  Misses      10147    10147           
  Partials      536      536           

Flag	Coverage Δ
unittests	48.82% <ø> (ø)

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