Add structured logging stacktrace hash field

[GollapudiSrikanth]

Summary

This PR adds support for emitting the stacktrace hash as a separate structured logging field, in addition to the existing inline format.

Details

Currently, when logging.structured.json.stacktrace.include-hashes is enabled, the hash is prefixed inline within the stack_trace field. While this is useful, it makes it harder to filter and group logs based on the hash value.

This change introduces new configuration properties:

logging.structured.stacktrace.hash.generate=inline | as-field
logging.structured.stacktrace.hash.field-name=stack_trace_hash

• inline preserves the existing behavior (default for backward compatibility)
• as-field emits the hash as a separate structured field
• field-name allows customization of the output field name

Backward Compatibility

• The existing property logging.structured.json.stacktrace.include-hashes is still supported in a deprecated form
• When set, it maps to the equivalent inline behavior
• The new properties take precedence if both are configured

Example

With:

logging.structured.stacktrace.hash.generate=as-field

Output:

{
  "stack_trace": "...",
  "stack_trace_hash": "351b6441"
}

Testing

• Added tests for:
• Inline mode (existing behavior)
• As-field mode
• Custom field name
• Deprecated property compatibility and precedence

Related Issue

Closes #49639

[snicoll]

Thanks for the PR. I spent quite a bit of time to review and try to adapt it but I am afraid we need to get back to the design and figure out how to integrate the feature. StackTraceHashFieldConfiguration, in particular, looks out of place to me and the change in the 6 constructors does not feel right to me. I'll flag the related issue team-only.