Fix duplicate network log.
Fix duplicate network log.

An early frontend change to the network panel duplicates network log
entries.

Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1103371
Change-Id: I553e10bb2116fb31de85ce87ed7399e83b76a2ff
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2288419
Reviewed-by: John Emau <c153e6e600be23fb28cec0b08551440e4bf7575d@microsoft.com>
Commit-Queue: Songtao Xia <efb39a3e57dd0e7c4fd137171d5e7a3f041d1da6@microsoft.com>

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