Update OWNERS for FileSystemProvider

It is a helper class for DocumentsProvider which is owned by the storage team.

Change-Id: I7355d6de4083f59ebbfd481f415ad70f5af996c3
BUG: 283962634
Test: n/a
diff --git a/core/java/com/android/internal/content/OWNERS b/core/java/com/android/internal/content/OWNERS
index c42bee6..c8e4005 100644
--- a/core/java/com/android/internal/content/OWNERS
+++ b/core/java/com/android/internal/content/OWNERS
@@ -1,5 +1,7 @@
 # Bug component: 36137
 include /core/java/android/content/pm/OWNERS
 
+per-file FileSystemProvider.java = file:/core/java/android/os/storage/OWNERS
+
 per-file ReferrerIntent.aidl = file:/services/core/java/com/android/server/am/OWNERS
 per-file ReferrerIntent.java = file:/services/core/java/com/android/server/am/OWNERS