Schema back reference does not output expected results.

[zong-zhe]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

x0 = Person {}

schema Person:
    name: str = "kcl"
    age: int = 1

2. What did you expect to see? (Required)

x0:
  name: kcl
  age: 1

3. What did you see instead (Required)

x0: {}

4. What is your KusionStack components version? (Required)

kclvm version is 0.4.3; checksum: e07ed7af0d9bd1e86a3131714e4bd20c