dissect: add 'f2fs' to allow-listed filesystems

f2fs is actively maintained upstream, and popular in certain device
categories (phones, embedded), so allow-list by default.

Fixes systemd/systemd#29026

(cherry picked from commit ee6cf8e)

Author: bluca

src/shared/dissect-image.c

@@ -99,6 +99,7 @@ int dissect_fstype_ok(const char *fstype) {
                                "btrfs",
                                "erofs",
                                "ext4",
+                               "f2fs",
                                "squashfs",
                                "vfat",
                                "xfs");