win: remove expired uma metrics in module_inspector.cc

Also remove Windows.IsPinnedToTaskbar2 from .xml file. Its use was
removed in crrev.com/c/3811669.

Bug: 984206
Change-Id: I65f2d450ed38c07dbf28b8c7fc2520a123107277
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3880886


Commit-Queue: David Bienvenu <davidbienvenu@chromium.org>
Reviewed-by: Patrick Monette <pmonette@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1045337}