tests: fix flaky kubecache test

[mmat11]

Fixes https://github.com/open-telemetry/opentelemetry-ebpf-instrumentation/actions/runs/22715844120/job/65865627754

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 43.90%. Comparing base (5f7d955) to head (c80c160).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1474   +/-   ##
=======================================
  Coverage   43.89%   43.90%           
=======================================
  Files         313      313           
  Lines       34216    34216           
=======================================
+ Hits        15019    15021    +2     
+ Misses      18220    18217    -3     
- Partials      977      978    +1     

Flag	Coverage Δ
integration-test	21.55% <ø> (ø)
integration-test-arm	0.00% <ø> (ø)
integration-test-vm-x86_64-5.15.152	?
integration-test-vm-x86_64-6.10.6	?
k8s-integration-test	2.29% <ø> (ø)
oats-test	0.00% <ø> (ø)
unittests	44.89% <ø> (+<0.01%)	⬆️

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