Remove references to RAW_PTR_EXCLUSION from VectorIconRep / VectorIcon

The spanification in https://crrev.com/c/5800255 already addressed these.

Fixed: 346694223, 346693938
Change-Id: If4f5327d07e40e6a441897bf5101d4e48bef518b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5815060


Auto-Submit: Mark Rowe <markrowe@chromium.org>
Reviewed-by: ccameron chromium <ccameron@chromium.org>
Commit-Queue: ccameron chromium <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1349311}