[o11y][nfc] Remove dependency on PipelineTracer

[fhanau]

Also see the downstream PR.

[codspeed-hq]

CodSpeed Performance Report

Merging #5519 will degrade performances by 8.59%

_{Comparing felix/111225-stw-simplify-2 (93e7d83) with main (78fce87)}

Summary

❌ 1 regression
✅ 52 untouched
⏩ 9 skipped¹

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	BASE	HEAD	Change
❌	simpleStringBody[Response]	20.5 µs	22.5 µs	-8.59%

Footnotes

1. 9 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩