Bump to latest upstream operator 1.15.5 #2886

Namespace: <a href="https://detailurl.setting.custom-console-url-namespace.is.not.configured" rel="nofollow">ocp-serverless-tenant
PipelineRun: <a href="https://console.redhat.com/application-pipeline/ns/ocp-serverless-tenant/pipelinerun/serverless-openshift-kn-operator-main-on-pull-request-qsxfw" rel="nofollow">serverless-openshift-kn-operator-main-on-pull-request-qsxfw

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Status	Duration	Name
✅ Succeeded	13 seconds	init
✅ Succeeded	16 seconds	clone-repository
✅ Succeeded	6 minutes	build-container
✅ Succeeded	8 seconds	build-image-index
✅ Succeeded	29 seconds	sast-snyk-check
✅ Succeeded	35 seconds	apply-tags
✅ Succeeded	1 minute	ecosystem-cert-preflight-checks
✅ Succeeded	55 seconds	build-source-image
✅ Succeeded	36 seconds	deprecated-base-image-check
✅ Succeeded	1 minute	clamav-scan
✅ Succeeded	4 minutes	clair-scan
✅ Succeeded	28 seconds	push-dockerfile
✅ Succeeded	25 seconds	show-sbom
✅ Succeeded	17 seconds	show-summary