[Fuchsia] Remove mention of enable_coverage_data.cml

Bug: 1432399
Change-Id: I98b095b1d1bb276ac333d5453ad3a4505d3c2f6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4566525


Commit-Queue: David Dorwin <ddorwin@chromium.org>
Auto-Submit: Chong Gu <chonggu@google.com>
Reviewed-by: David Dorwin <ddorwin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1149135}