Fix persistence extensions test reliability

[mherwege]

See discussion: #4818 (comment)

This reduces the impact of now() on the persistence extensions test reliability. There only was a major impact for average on OnOff types. This impact has been removed by not testing the AverageSince and AverageUntil methods, only the AverageBetween method.

@jimtng @Nadahar FYI

EDIT: I am running the tests with a sleep of 1 minute on every query to the persistence service. If this succeeds, I consider the persistence extension tests to be independent from the current time for all practical purposes.

[Copilot]

Pull Request Overview

This PR fixes reliability issues in persistence extensions tests by reducing the impact of timing dependencies on test outcomes. The main change is eliminating tests that rely on the current time (now()) for OnOff type average calculations, specifically removing AverageSince and AverageUntil tests in favor of only testing AverageBetween.

Key changes:

• Replaces hardcoded year values with dynamic calculations based on current year to reduce time dependencies
• Removes time-sensitive average tests for OnOff types (AverageSince and AverageUntil)
• Consolidates Riemann sum tests to use only RiemannSumBetween method
• Includes commented-out debugging code for adding delays to test queries

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
TestPersistenceService.java	Updates hardcoded year constants to be relative to current year and adds a now() helper method
TestCachedValuesPersistenceService.java	Adds commented debugging code for introducing delays in persistence queries
PersistenceExtensionsTest.java	Removes AverageSince/AverageUntil tests and consolidates to AverageBetween tests only

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[mherwege]

I have removed 2 more tests to reduce potential issues. All remaining tests now work even if there would be a 1 minute delay in the persistence query (tested with 1 minute, but I expect it can even be more). I think that should cover stability issues.

[mherwege]

This is now ready for review.

[holgerfriedrich]

Thanks!