install: Drop Lightspeed CustomResourceDefinitions (Proposal, etc.)

These are now conveniently installed in test clusters via [1], so we
can demo tech-preview Proposal creation with the agentic Lightspeed
operator installed, without having to install the CRDs ourselves.
Reverts 4936d65 (OTA-1965: Add Lightspeed
CustomResourceDefinitions, 2026-04-21, #1380).  This adjusts the
approach 8520979 (OTA-1967: Take official CRDs from the OpenShift
Lightspeed operator, 2026-05-08, #1380) had taken, by pushing CRD
handling over to Lightspeed, instead of leaving the CVO on the hook to
deploy Lightspeed's CRDs for them, now that the Lightspeed quickstart
makes Lightspeed-manages-its-own-CRDs so easy.

[1]: https://github.com/openshift/lightspeed-agentic-operator/tree/main/hack/quickstart

Author: wking