Invalid runtime union type check that contains utf-8 chars

[Peefy]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

• Write KCL Code (main.k)

schema Data:
    msg: "无需容灾" | "标准型" | "流水型" = "流水型"

data = Data()

kcl main.k

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

The yaml output:

data:
  msg: 流水型

3. What did you see instead (Required)

The error message

EvaluationError
 --> main.k:2:1
  |
2 |     msg: "无需容灾" | "标准型" | "流水型" = "流水型"
  |  byte index 17 is not a char boundary; it is inside '标' (bytes 16..19) of `"无需容灾"|"标准型"|"流水型"`
  |

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

kcl-v0.5.0-beta.1