Revert "Fix debug string for validateTraceCategories error."
Revert "Fix debug string for validateTraceCategories error."

This reverts commit fd97b5ad59de0a447b2eb455292892dad65ebe0a.

Reason for revert: similar debugging info is present in the trace itself.

Original change's description:
> Fix debug string for validateTraceCategories error.
> 
> Handle new metadata dict. Also add missing parenthesis.
> 
> Bug: chromium:919187
> Change-Id: Id86daa13a3500d2a39418a14fb8c0ef2b52b296f
> Reviewed-on: https://chromium-review.googlesource.com/c/1449696
> Commit-Queue: Ben Hayden <benjhayden@chromium.org>
> Reviewed-by: Ben Hayden <benjhayden@chromium.org>
> Auto-Submit: Eric Seckler <d661906de75c240343b01bf83bdad954d5d7d8b2@chromium.org>

TBR=benjhayden@chromium.org,d661906de75c240343b01bf83bdad954d5d7d8b2@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:919187
Change-Id: Ic23b86e9dbe188f25958910897e94f5c8b1d0f4a
Reviewed-on: https://chromium-review.googlesource.com/c/1466343
Reviewed-by: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>
Commit-Queue: Eric Seckler <d661906de75c240343b01bf83bdad954d5d7d8b2@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult