Omit file existence check on notifyDexContainersLoaded.

This is due to sepolicy restrictions on some platforms.

Bug: 401662336
Bug: 391895923
Test: atest ArtServiceTests
Test: app-debug.apk in b/391895923#comment3
Flag: EXEMPT bugfix
(cherry picked from commit d62d66437f3b322f202c314672fbaf810fde7142)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:9b3a1588981ca33693081a507744819871e5ca7f)
Merged-In: Ib6d878a678ddafd02fb48d92ddfbabdfd6f4f14e
Change-Id: Ib6d878a678ddafd02fb48d92ddfbabdfd6f4f14e