[lensoverlay] Handle device pixel ratio changes

Since we rely on window.devicePixelRatio, we need to ensure we update
our UI anytime the pixel ratio changes.

Bug: b/350613328
Change-Id: I41da9e47d28291ba20cd01228e693dfad53a95b1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5684223


Reviewed-by: Bryan Nguyen <nguyenbryan@google.com>
Commit-Queue: Duncan Mercer <mercerd@google.com>
Cr-Commit-Position: refs/heads/main@{#1324398}