net/freerdp: update to 2.11.6 with 6 CVEs fixed

Changelog:
https://github.com/FreeRDP/FreeRDP/releases/tag/2.11.6

CVE:
CVE-2024-32041 [Low[ OutOfBound Read in zgfx_decompress_segment
CVE-2024-32039 [Moderate] Integer overflow & OutOfBound Write in clear_decompress_residual_data
CVE-2024-32040 [Low] integer underflow in nsc_rle_decode
CVE-2024-32458 [Low] OutOfBound Read in planar_skip_plane_rle
CVE-2024-32459 [Low] OutOfBound Read in ncrush_decompress
CVE-2024-32460 [Low] OutOfBound Read in interleaved_decompress

Approved by: arrowd (mentor, implicit)
MFH: 2024Q2

(cherry picked from commit 78ae5b8b3407d78026445efdc53ab6a8c37b6622)