Update failsafe.html

fix for gps_rescue_descent_dist according to cli command
```# get gps_rescue_descent_dist
gps_rescue_descent_dist = 20
Allowed range: 10 - 500
```

src/tabs/failsafe.html

@@ -129,7 +129,7 @@
                                     </label>
                                 </div>
                                 <div class="number">
-                                    <label> <input type="number" name="gps_rescue_descent_distance" min="30" max="500" /> <span
+                                    <label> <input type="number" name="gps_rescue_descent_distance" min="10" max="500" /> <span
                                         i18n="failsafeGpsRescueItemDescentDistance"></span>
                                     </label>
                                 </div>