fs_mgr: avoid vector<const T>

A container of const T uses std::allocator<const T>, which was an
undocumented libc++ extension that has been removed.

See https://github.com/llvm/llvm-project/pull/96319.

Bug: 349681543
Test: m libfs_mgr
Change-Id: Ic7f50453f05293b7684be22393d6e5871e493983
diff --git a/fs_mgr/fs_mgr_overlayfs_mount.cpp b/fs_mgr/fs_mgr_overlayfs_mount.cpp
index bd0fcfd..b63b9e7 100644
--- a/fs_mgr/fs_mgr_overlayfs_mount.cpp
+++ b/fs_mgr/fs_mgr_overlayfs_mount.cpp
@@ -74,7 +74,7 @@
     return android::gsi::IsGsiRunning();
 }
 
-std::vector<const std::string> OverlayMountPoints() {
+std::vector<std::string> OverlayMountPoints() {
     // Never fallback to legacy cache mount point if within a DSU system,
     // because running a DSU system implies the device supports dynamic
     // partitions, which means legacy cache mustn't be used.
diff --git a/fs_mgr/fs_mgr_overlayfs_mount.h b/fs_mgr/fs_mgr_overlayfs_mount.h
index 98b9007..f941ab1 100644
--- a/fs_mgr/fs_mgr_overlayfs_mount.h
+++ b/fs_mgr/fs_mgr_overlayfs_mount.h
@@ -54,7 +54,7 @@
 bool OverlayfsSetupAllowed(bool verbose = false);
 bool MountScratch(const std::string& device_path, bool readonly = false);
 bool fs_mgr_overlayfs_umount_scratch();
-std::vector<const std::string> OverlayMountPoints();
+std::vector<std::string> OverlayMountPoints();
 bool fs_mgr_overlayfs_already_mounted(const std::string& mount_point, bool overlay_only = true);
 bool fs_mgr_wants_overlayfs(android::fs_mgr::FstabEntry* entry);
 android::fs_mgr::Fstab fs_mgr_overlayfs_candidate_list(const android::fs_mgr::Fstab& fstab);
diff --git a/fs_mgr/fs_mgr_vendor_overlay.cpp b/fs_mgr/fs_mgr_vendor_overlay.cpp
index 6b742e5..6687283 100644
--- a/fs_mgr/fs_mgr_vendor_overlay.cpp
+++ b/fs_mgr/fs_mgr_vendor_overlay.cpp
@@ -36,7 +36,7 @@
 
 // The order of the list means the priority to show the files in the directory.
 // The last one has the highest priority.
-const std::vector<const std::string> kVendorOverlaySourceDirs = {
+const std::vector<std::string> kVendorOverlaySourceDirs = {
         "/system/vendor_overlay/",
         "/product/vendor_overlay/",
 };