[roll] Roll fuchsia [sestarnix] Unify compute_create_context API

Replaces `compute_create_context` and `compute_create_context_with_name`
(and `compute_new_fs_node_sid` helpers) with a single unified API that
accepts a target object `name: &[u8]` slice.

Passing an empty slice (`&[]`) evaluates standard nameless creation
transitions, while a non-empty slice evaluates filename-based
transition rules first. This removes duplicate API entrypoints and
simplifies `SecurityServer`, `PermissionCheck`, and `AccessVectorCache`.

Additionally updates SELinuxFS `/sys/fs/selinux/create` to parse and
pass optional trailing filename arguments to `compute_create_sid_raw`
instead of returning `ENOTSUP`.

Original-Original-Bug: 527401888
Test: fx test starnix-selinux-unit-tests
TAG: agy
CONV: dcb536c7-19df-4835-aed2-866ffd287edf
Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1744093
Original-Original-Revision: 22288c2c4eb64f25e93a83c15e61fc984d138a2d
GitOrigin-RevId: 33e8b8013e1e38449a2a9469867449e449c1e053
Change-Id: Id5fab2e486bd641342585e9782e01a6acf0167b7
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1746430
Cr-Commit-Position: refs/heads/main@{#198822}