DO NOT MERGE Apply a maximum char count to the load label api

The system is overwhelmed by an enormous label string returned by
the load label api. This cl truncates the label string if it exceeds
the maximum safe length.

Bug: 67013844
Test: atest PackageManagerTest
Change-Id: Ia4d768cc93a47cfb8b6f7c4b6dc73abd801809bd
1 file changed