CLSA-2026-1771407667 freerdp: Fix of CVE-2026-22856

CVE-2026-22856: fix heap use-after-free in createirpthread...

CVE-2026-22856 FreeRDP has a heap-use-after-free in create_irp_thread

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.20.1, a race in the serial channel IRP thread tracking allows a heap use‑after‑free when one thread removes an entry from serial-IrpThreads while another reads it. This vulnerability is fixed in 3.20.1...