fix: make phase spans siblings under package span

Phase spans were nesting under each other because the package context
was being updated to the phase context. Keep the original package
context so all phases are direct children of the package span.

Co-authored-by: Ona <no-reply@ona.com>

Author: WVerlaek

pkg/leeway/reporter.go

@@ -941,7 +941,7 @@ func (r *OTelReporter) PackageBuildPhaseStarted(pkg *Package, phase PackageBuild
 
 	// Create phase span as child of package span
 	phaseKey := fmt.Sprintf("%s:%s", pkgName, phase)
-	ctx, span := r.tracer.Start(packageCtx, "leeway.phase",
+	_, span := r.tracer.Start(packageCtx, "leeway.phase",
 		trace.WithSpanKind(trace.SpanKindInternal),
 	)
 
@@ -950,9 +950,7 @@ func (r *OTelReporter) PackageBuildPhaseStarted(pkg *Package, phase PackageBuild
 		attribute.String("leeway.phase.name", string(phase)),
 	)
 
-	// Store phase span and update package context
 	r.phaseSpans[phaseKey] = span
-	r.packageCtxs[pkgName] = ctx
 }
 
 // PackageBuildPhaseFinished implements PhaseAwareReporter