[PLT-1691] Simplify get_label_filter_order test

[vbrodsky]

Description

The test_label_filter_order test fails consistently on prod for some but not all runs. See here as an example. I have simplified the test to make sure it will be less subjected to timing / concurrency

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Document change (fix typo or modifying any markdown files, code comments or anything in the examples folder only)

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