Upgrade the guerrilla import of ABSL. am: 6f56677b3f

Original change: https://android-review.googlesource.com/c/platform/external/libtextclassifier/+/2908817

Change-Id: I7f0bc80c68d9c92c98edd41ce84d574d83c6db84
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>