Updates the Stan submodule to f8e696908.

stan-buildbot · stan-buildbot · commit 3973387c9ba1 · 2025-06-17T00:24:43.000-04:00
diff --git a/stan b/stan
@@ -1 +1 @@
-Subproject commit b83f95f1f072b3d144161d61ea79fe4550b21573
+Subproject commit f8e696908790cb6719c3824e00fa1d7aa46a0581
