Update knowhere version (#23769)

Signed-off-by: NYudong Cai <yudong.cai@zilliz.com>

internal/core/thirdparty/knowhere/CMakeLists.txt

@@ -11,7 +11,7 @@
 # or implied. See the License for the specific language governing permissions and limitations under the License.
 #-------------------------------------------------------------------------------
 
-set( KNOWHERE_VERSION 6d26f1f )
+set( KNOWHERE_VERSION 6448cf09)
 
 message(STATUS "Building knowhere-${KNOWHERE_SOURCE_VER} from source")
 message(STATUS ${CMAKE_BUILD_TYPE})