[cherry-pick] Modify the schedule cases.

[blackpiglet]

• Modify the OrderResource case's verification code.
• Simplify the Periodical case.
• Simplify the InProgess case.
• Prettify the code.
• Replace math/rand with crypto/rand
• Replace PollUnitl with PollUntilContextTimeout

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Fixes #(issue)

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• Created a changelog file (make new-changelog) or comment /kind changelog-not-required on this PR.
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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.11%. Comparing base (49a8e24) to head (57f873b).
Report is 2 commits behind head on release-1.15.

Additional details and impacted files

@@               Coverage Diff                @@
##           release-1.15    #8531      +/-   ##
================================================
- Coverage         59.12%   59.11%   -0.02%     
================================================
  Files               367      367              
  Lines             39118    39118              
================================================
- Hits              23130    23126       -4     
- Misses            14520    14523       +3     
- Partials           1468     1469       +1     

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