RSDK-6116: Mobile app should auto refresh board's analog readings (#185)

* RSDK-6116: Mobile app should auto refresh board's analog readings

* Cancel timer when widget is destroyed

* Made refreshInterval settable by user

* Added docstring

lib/widgets/resources/board.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:viam_sdk/viam_sdk.dart';
@@ -12,9 +14,14 @@ class ViamBoardWidget extends StatefulWidget {
   /// The [Board]
   final Board board;
 
+  /// The refresh interval
+  /// This field determines how frequently the user wants to auto refresh the board's status readings.
+  final Duration refreshInterval;
+
   const ViamBoardWidget({
     super.key,
     required this.board,
+    this.refreshInterval = const Duration(seconds: 1),
   });
 
   @override
@@ -34,6 +41,8 @@ class _ViamBoardWidgetState extends State<ViamBoardWidget> {
   final _pwmFreqFormKey = GlobalKey<FormState>();
   int pwmFrequency = 0;
 
+  Timer? timer;
+
   BoardStatus status = const BoardStatus({}, {});
 
   Future<void> _fetchStatus() async {
@@ -43,10 +52,27 @@ class _ViamBoardWidgetState extends State<ViamBoardWidget> {
     });
   }
 
+  void refresh() {
+    _fetchStatus();
+  }
+
+  void _createTimer() {
+    timer = Timer.periodic(widget.refreshInterval, (_) {
+      refresh();
+    });
+  }
+
   @override
   void initState() {
     super.initState();
     _fetchStatus();
+    _createTimer();
+  }
+
+  @override
+  void dispose() {
+    timer?.cancel();
+    super.dispose();
   }
 
   void _dismissKeyboard() {