[FLEDGE] Delete WPT ini files to clean up the directory.

These files are no longer used. Delete them to make navigating the
ever-growing amount of test files a little more user-friendly.

Bug: 1492264
Change-Id: Ib9f95ca00f13d61c4a449fe52619b112c3bfc379
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4993790
Reviewed-by: Maks Orlovich <morlovich@chromium.org>
Commit-Queue: Matt Menke <mmenke@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1217663}