[Backport release-1.5] Fix: address failure when rendering addon API schemas (#4445)

* Fix: address failure when rendering addon API schemas

Signed-off-by: Charlie Chiang <charlie_c_0129@outlook.com>
(cherry picked from commit de7a64346c)

* Fix: address failure when rendering addon API schemas

Signed-off-by: Charlie Chiang <charlie_c_0129@outlook.com>
(cherry picked from commit 284e673bad)

* Test: add tests

Signed-off-by: Charlie Chiang <charlie_c_0129@outlook.com>
(cherry picked from commit 1c0653e449)

* Test: fix tests

Signed-off-by: Charlie Chiang <charlie_c_0129@outlook.com>
(cherry picked from commit 78104068b1)

* Test: fix tests

Signed-off-by: Charlie Chiang <charlie_c_0129@outlook.com>
(cherry picked from commit 0442f823c8)

Co-authored-by: Charlie Chiang <charlie_c_0129@outlook.com>

pkg/addon/testdata/example/template.cue

@@ -0,0 +1,27 @@
+output: {
+	apiVersion: "core.oam.dev/v1beta1"
+	kind:       "Application"
+	metadata: {
+		name:      "example"
+		namespace: "vela-system"
+	}
+	spec: {
+		workflow: steps: [{
+			name: "apply-ns"
+			type: "apply-component"
+			properties: component: "ns-example-system"
+		}, {
+			name: "apply-resources"
+			type: "apply-remaining"
+		}]
+		components: [{
+			name: "ns-example-system"
+			type: "raw"
+			properties: {
+				apiVersion: "v1"
+				kind:       "Namespace"
+				metadata: name: "example-system"
+			}
+		}]
+	}
+}

pkg/addon/testdata/example/template.yaml

@@ -1,22 +0,0 @@
-apiVersion: core.oam.dev/v1beta1
-kind: Application
-metadata:
-  name: example
-  namespace: vela-system
-spec:
-  workflow:
-    steps:
-      - name: apply-ns
-        type: apply-component
-        properties:
-          component: ns-example-system
-      - name: apply-resources
-        type: apply-remaining
-  components:
-    - name: ns-example-system
-      type: raw
-      properties:
-        apiVersion: v1
-        kind: Namespace
-        metadata:
-          name: example-system