jobs: move trace_id from payload to progress

The trace_id associated with a job is updated on every
resumption of the job. If the job is paused and resumed
several times, we don't want to rewrite the payload every
single time. Thus, we move the field to the job progress
which is expected to be rewritten frequently.

Also addresses a comment from cockroachdb#65322.

Release note: None

pkg/jobs/adopt.go

@@ -255,17 +255,15 @@ func (r *Registry) runJob(
 	//
 	// A new root span will be created on every resumption of the job.
 	var spanOptions []tracing.SpanOption
-	if tj, ok := resumer.(TraceableJob); ok {
-		if tj.ForceRealSpan() {
-			spanOptions = append(spanOptions, tracing.WithForceRealSpan())
-		}
+	if _, ok := resumer.(TraceableJob); ok {
+		spanOptions = append(spanOptions, tracing.WithForceRealSpan())
 	}
 	ctx, span = r.settings.Tracer.StartSpanCtx(ctx, spanName, spanOptions...)
 	defer span.Finish()
 	if err := job.Update(ctx, nil /* txn */, func(txn *kv.Txn, md JobMetadata,
 		ju *JobUpdater) error {
-		md.Payload.TraceID = span.TraceID()
-		ju.UpdatePayload(md.Payload)
+		md.Progress.TraceID = span.TraceID()
+		ju.UpdateProgress(md.Progress)
 		return nil
 	}); err != nil {
 		return err

pkg/jobs/jobs.go

@@ -97,7 +97,7 @@ type StartableJob struct {
 type TraceableJob interface {
 	// ForceRealSpan forces the registry to create a real Span instead of a
 	// low-overhead non-recordable noop span.
-	ForceRealSpan() bool
+	ForceRealSpan()
 }
 
 func init() {