[res] Fix registerResourcePaths crash with bad path

Make sure that when we're adding new paths to existing Resources
objects this doesn't throw an unexpected exception to the
API caller. Instead, it's better to skip updating any existing
objects that fail loading - those can't be used correctly
anymore anyway
(the usual issue is when there's an object that hasn't been
collected yet, so it is irrelevant to the app correctness)

+ Add a unit test for this exact scenario

Bug: 405913316
Flag: EXEMPT small bugfix
Test: atest ResourcesManagerTest

Change-Id: I0fc33770dbf2932c2946ed702ed7d5b2c3dde04b