Update libsession-util to 1.5.6

SessionHero01 · SessionHero01 · commit 1bf81a7b1b80 · 2025-09-24T11:41:22.000+08:00
diff --git a/libsession-util b/libsession-util
@@ -1 +1 @@
-Subproject commit 5e3835bcfa7202cf307bc299bb1e40e160e8d357
+Subproject commit c73fd92eb71e8108cc435fc640fbcb8faceacbb0
