feat(gcp_stackdriver_logs sink): Support user-defined insertId

[garethpelly]

Summary

This adds support for setting a custom insertId at the root level of the LogEntry, allowing users to define their own unique identifier for each log entry.

In a similar way to how the severity_key field works with the sink now, we extract a custom insertId from log events via an insert_id_key configuration option. The named field is removed from the log event if present.

Vector configuration

sources:
  dummy_logs:
    type: "demo_logs"
    format: "syslog"
    interval: 1

transforms:
  parse_logs:
    type: "remap"
    inputs: ["dummy_logs"]
    source: |
      . = parse_syslog!(string!(.message))
      .my_insert_id = uuid_v4()

sinks:
  my_sink_id:
    type: gcp_stackdriver_logs
    project_id: "my-project"
    log_id: "test_log"
    inputs:
      - parse_logs
    insert_id_key: "my_insert_id"
    resource:
      type: "gce_instance"
      project_id: "my-project"
      instanceId: "Twilight"
      zone: "us-central1-a"

How did you test this PR?

• Ran unit tests
• Tested using my Google account and inspected logs in Google Cloud Logging

Change Type

• Bug fix
• New feature
• Dependencies
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Closes: Support user-defined insertId in gcp_stackdriver_logs sink #24967

Notes

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[OliviaShoup]

thanks for the PR! 🚀