fix: Add controller-gen to CI build root image

[aali309]

What type of PR is this?

This change adds controller-gen to the CI build root image.

/kind bug

What does this PR do / why we need it:
This change adds controller-gen to the CI build root image to fix test failures when running with GOFLAGS=-mod=vendor. Previously, the CI environment would fail when trying to download controller-gen during test execution due to
the vendor flag preventing module downloads.
Have you updated the necessary documentation?

• Documentation update is required by this PR.
• Documentation has been updated.

Which issue(s) this PR fixes:

Fixes #?

Test acceptance criteria:

• Unit Test
• E2E Test

How to test changes / Special notes to the reviewer:

[openshift-ci]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[openshift-ci]

@aali309: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/v4.17-e2e	9af14fe	link	true	/test v4.17-e2e
ci/prow/v4.14-kuttl-sequential	9af14fe	link	true	/test v4.14-kuttl-sequential
ci/prow/v4.14-kuttl-parallel	9af14fe	link	true	/test v4.14-kuttl-parallel
ci/prow/v4.14-e2e	9af14fe	link	true	/test v4.14-e2e
ci/prow/v4.17-kuttl-sequential	9af14fe	link	true	/test v4.17-kuttl-sequential
ci/prow/v4.17-kuttl-parallel	9af14fe	link	true	/test v4.17-kuttl-parallel
ci/prow/unit	2f4984c	link	true	/test unit

Full PR test history. Your PR dashboard.

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