Test Flux v2.3 release candidate with CRD load

[stefanprodan]

Changes to benchmark:

• Update Flux to v2.3 (pre-releaase images and CRDs)
• Update Kubernetes to v1.29
• Pre-install CRDs 50/250/500 to check if Flux performance is affected by a large number of API extensions

Preliminary results:

• Compared to Flux 2.2 and Kubernetes 1.28 we observe no performance regression in Flux 2.3 and Kubernetes 1.29
• Compared to Flux 2.2 and Kubernetes 1.28 where large number of CRDs would drive helm-controller into OOM, in Flux 2.3 and Kubernetes 1.29, even with 500 CRDs, helm-controller reconciles 1K HelmReleases in under 9 minutes when configured with concurrent 10, 2CPU and 1GB RAM limits.