[Bug]: bvt panic when errorMessage is nil but it should not

[jensenojs]

Is there an existing issue for the same bug?

• I have checked the existing issues.

Environment

- Version or commit-id (e.g. v0.1.0 or 8b23a93):4426837
- Hardware parameters:
- OS type:
- Others:

Actual Behavior

Expected Behavior

continue run bvt cases

Steps to Reproduce

No response

Additional information

No response