Update CI pipeline to pass the built Docker image to integration tests as a file artifact instead of pulling from a registry.
Adds explicit list of integration tests to build-image job outputs logic
Adds step to export charon:local image to tarball in linux/amd64 architecture
Updates integration jobs to download and load the image artifact
Resolves "invalid reference format" errors when registry tags are missing or invalid
Enables integration testing on PRs that do not push to registry