[BugFix] Fix failing gemma-3-1b-it test:...

[BugFix] Fix failing gemma-3-1b-it test: `test_lm_eval_accuracy_v1_engine[google/gemma-3-1b-it]` (#27111)
Signed-off-by: Lucas Wilkinson <lwilkins@redhat.com>

cmake/external_projects/vllm_flash_attn.cmake

@@ -38,7 +38,7 @@ else()
   FetchContent_Declare(
           vllm-flash-attn
           GIT_REPOSITORY https://github.com/vllm-project/flash-attention.git
-          GIT_TAG 8f468e7da54a8e2f98abfa7c38636aac91c0cba1
+          GIT_TAG a893712401d70362fbb299cd9c4b3476e8e9ed54
           GIT_PROGRESS TRUE
           # Don't share the vllm-flash-attn build between build types
           BINARY_DIR ${CMAKE_BINARY_DIR}/vllm-flash-attn