Update fastcdr submodule to v2.3.1 (#6038) (#6041)

mergify[bot] · MiguelCompany · web-flow · commit e626fd6a3561 · 2025-09-17T14:55:56.000+02:00
(cherry picked from commit 5c31247) Signed-off-by: Miguel Company <miguelcompany@eprosima.com> Co-authored-by: Miguel Company <miguelcompany@eprosima.com>
diff --git a/thirdparty/fastcdr b/thirdparty/fastcdr
@@ -1 +1 @@
-Subproject commit f55d548e04739c9e0cf332d72de1d440b14af797
+Subproject commit c931bdefefcecb6f852ef7be02369f9d740d6929
