Adding details after a flag is not found in MotionFlags

Because from_bits will return a None if we encounter a flag that we
can't find, and if we call unwrap directly we will have a crash, but the
crash message here will confuse us, so here we add some detailed
information to help us locate the problem later.

Bug: none
Test: Build

Signed-off-by: Linnan Li <lilinnan@xiaomi.corp-partner.google.com>
(cherry picked from https://partner-android-review.googlesource.com/q/commit:2d17392f625885a7a4e49bad59f5793223c73dda)
Merged-In: If3970964ef696e22dc651579a4c297f431b3e0ca
Change-Id: If3970964ef696e22dc651579a4c297f431b3e0ca