[Bug]: use hash values for operation id in history

### Expected Behavior

Operation id should be a unique string instead of a number in execution history so that we can support more levels of child context

### Actual Behavior

Operation id is currently a number

### Steps to Reproduce

NA

### SDK Version

0.5

### Java Version

17

### Is this a regression?

No

### Last Working Version

_No response_

### Additional Context

_No response_