Fix catalogd-crd-diff CI check

The check fails because the CRD does not exist in the new repo.
    We are improving the CI and makefile target to skip when the orginal
    does not exist.

catalogd/Makefile

@@ -134,7 +134,12 @@ CRD_DIFF_ORIGINAL_REF := main
 CRD_DIFF_UPDATED_SOURCE := file://config/base/crd/bases/olm.operatorframework.io_clustercatalogs.yaml
 CRD_DIFF_CONFIG := crd-diff-config.yaml
 verify-crd-compatibility: $(CRD_DIFF)
-	$(CRD_DIFF) --config="${CRD_DIFF_CONFIG}" "git://${CRD_DIFF_ORIGINAL_REF}?path=config/base/crd/bases/olm.operatorframework.io_clustercatalogs.yaml" ${CRD_DIFF_UPDATED_SOURCE}
+	@if git show ${CRD_DIFF_ORIGINAL_REF}:config/base/crd/bases/olm.operatorframework.io_clustercatalogs.yaml > /dev/null 2>&1; then \
+		echo "Running CRD diff..."; \
+		$(CRD_DIFF) --config="${CRD_DIFF_CONFIG}" "git://${CRD_DIFF_ORIGINAL_REF}?path=config/base/crd/bases/olm.operatorframework.io_clustercatalogs.yaml" ${CRD_DIFF_UPDATED_SOURCE}; \
+	else \
+		echo "Skipping CRD diff: CRD does not exist in ${CRD_DIFF_ORIGINAL_REF}"; \
+	fi
 
 .PHONY: lint
 lint: $(GOLANGCI_LINT) ## Run golangci linter.