[DevTools] Update tooltip text for HAR import/export

Change-Id: I4c34f9a25945001f292fc8a8f1d45152b36fde34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1627561
Reviewed-by: Joel Einbinder <einbinder@chromium.org>
Reviewed-by: Erik Luo <luoe@chromium.org>
Reviewed-by: Paul Irish <paulirish@chromium.org>
Commit-Queue: Joey Arhar <jarhar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663336}
1 file changed