Use byte count rather than string length for NMS component name check

Bug: 505067993
Test: atest NotificationManagerServiceTest
Flag: EXEMPT BUGFIX
(cherry picked from commit 577543980a006ea56dd3fbbb3e7e4d28bb0db4d8)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:a6fc2d471a7529428330e9fbf2de5866fd449aef
Merged-In: Ie1bf232340770e1237f80177bb0b86eabeda3635
Change-Id: Ie1bf232340770e1237f80177bb0b86eabeda3635
2 files changed