west.yml: hal_stm32: revert ble_fw blobs

Since the mkbox board ble f/w upgrade method based on binary
blobs that was proposed in zephyrproject-rtos#74255 has been turned down, all
the work done in hal_stm32 module to host blobs is now reverted.

Signed-off-by: Armando Visconti <armando.visconti@st.com>

west.yml

@@ -233,7 +233,7 @@ manifest:
       groups:
         - hal
     - name: hal_stm32
-      revision: 1e6116bd2a36db976d955ee772d21f329e529873
+      revision: 1ff820533c1b1c17f1a4d7d28ab99a94a234883b
       path: modules/hal/stm32
       groups:
         - hal