commander_params: shorten low battery action delay

I got multiple times the feedback now that a consistent delay
is helpful and makes sense but the default delay
is too long
for low battery action where you're trying to come back in time
and possibly the emergency reaction kicks in while the critical action
is executing which leads to a longer accumulated delay.

src/modules/commander/commander_params.c

@@ -296,7 +296,7 @@ PARAM_DEFINE_INT32(COM_LOW_BAT_ACT, 0);
  * @max 25.0
  * @decimal 3
  */
-PARAM_DEFINE_FLOAT(COM_BAT_ACT_T, 10.0f);
+PARAM_DEFINE_FLOAT(COM_BAT_ACT_T, 5.f);
 
 /**
  * Imbalanced propeller failsafe mode