[security-aosp-25Q2-staging] Remove default ignoreable characters before regex checks

This is a combined CL for cherry-pick. Original CLs merged in main-
ag/33577707
ag/33920560
ag/33920560

Lower file system ignores certain characters while saving files.
Malicious apps use these ignorable characters to by-pass regex checks
that are needed to protect private app directories. We remove these
characters before regex checks so that apps cannot by-pass the checks.

Bug: 377888957
Test: atest com.android.providers.media.util.FileUtilsTest#testNormalizeAndFilterDefaultIgnorableCodepoints
Test: atest com.android.providers.media.util.FileUtilsTest#testIsDataOrObbRelativePathWithZwsChars_flagEnabled
Test: atest com.android.providers.media.util.FileUtilsTest#testIsDataOrObbRelativePathWithZwsChars_flagDisabled
Flag: com.android.providers.media.flags.enable_path_sanitization
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:ac3a6dc8db818a74357af1dfa2acfa911648827c)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:2ce2b01a309edcd4e28460225dc5f2cc36d6597c
Merged-In: Ibb96bda4b4fdb0869209aeb37260bf656d155a9e
Change-Id: Ibb96bda4b4fdb0869209aeb37260bf656d155a9e