Remove e2e test dependency on injection informers

[pierDipi]

This helps with testing upgrades when there are new CRDs (like EventPolicy)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 48.55%. Comparing base (76e67cd) to head (6d82cc8).
Report is 9 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4099   +/-   ##
=======================================
  Coverage   48.55%   48.55%           
=======================================
  Files         244      244           
  Lines       14825    14825           
=======================================
  Hits         7199     7199           
  Misses       6912     6912           
  Partials      714      714           

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[creydr]

/lgtm

[knative-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: creydr, pierDipi

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[pierDipi]

/retest-required

[pierDipi]

/test upgrade-tests

[creydr]

/retest

[pierDipi]

/test upgrade-tests

[pierDipi]

/retest-required

[knative-prow]

@pierDipi: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
upgrade-tests_eventing-kafka-broker_main	6d82cc8	link	true	/test upgrade-tests

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