Fix: Fix output

[shivin]

Description of your changes

Fixes #6734
We looked at the issue and debugged the code. We added following fixes to fix the issue:

1. Add backward compatibility for workflow outputs with builtin function.
2. We observed extra quotes coming in the string written to configmap. Replaced util.ToString to sets.ToString in writeToStore function.
   I have:

• Read and followed KubeVela's contribution process.
• Related Docs updated properly. In a new feature or configuration option, an update to the documentation is necessary.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR if necessary.

How has this code been tested

We tested the code by applying KubeVela application and verified the output is proper.

apiVersion: core.oam.dev/v1beta1
kind: Application
metadata:
  name: test-app
spec:
  components: []
  workflow:
    steps:
      - name: read-secret
        type: read-object
        properties:
          apiVersion: v1
          kind: Secret
          name: mysecret
        outputs:
          - name: mypasswor1
            valueFrom: |-
              import "encoding/base64"
              "\(base64.Decode(null,output.value.data["password"] ))"

Data in ConfigMap:

apiVersion: v1
data:
  vars: |
    mypasswor1: "mypassword"
kind: ConfigMap

Special notes for your reviewer