[pinpoint] Retry taskqueue.add() on taskqueue.TransientError.
[pinpoint] Retry taskqueue.add() on taskqueue.TransientError.

Bug: catapult:#4526
Change-Id: Ic9ca1d08151c4a1d8eb952131e0657716d4ba1b6
Reviewed-on: https://chromium-review.googlesource.com/1114394
Reviewed-by: Juan Antonio Navarro Pérez <1649bb5e6b9eafe026580e338065dc64ba6b80b2@chromium.org>
Commit-Queue: David Tu <baa605d781958521249fdcf7bad76b01d943134a@chromium.org>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult