Fix typo in unregistering pointerup event listener
Fix typo in unregistering pointerup event listener

R=dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org

Fixed: 1289120
Change-Id: I024021b9a74a027192b8bd25e3a17015d0139147
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3404092
Commit-Queue: Yang Guo <1cf0af8245a3a17a632a2c73531392b0f9761c76@chromium.org>
Auto-Submit: Yang Guo <1cf0af8245a3a17a632a2c73531392b0f9761c76@chromium.org>
Reviewed-by: Tim Van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>
Commit-Queue: Tim Van der Lippe <dba8716ee7f8d16236046f74d2167cb94410f6ed@chromium.org>

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