Implement scan filter in example app (#61)

* Implement scan filter in example app

* Remove Fixed FlutterVersion from Workflow and improve ScanFilterWidget

* Update example/lib/home/widgets/scan_filter_widget.dart

* Update example/lib/home/widgets/scan_filter_widget.dart

* Update example/lib/peripheral_details/peripheral_detail_page.dart

* Improve text

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Co-authored-by: Foti Dim <foti@navideck.com>
Co-authored-by: Foti Dim <fdimanidis@gmail.com>

.github/workflows/build_web_app.yml

@@ -14,7 +14,6 @@ jobs:
       - name: Setup Flutter
         uses: subosito/flutter-action@v2
         with:
-          flutter-version: '3.16.0'
           channel: 'stable'
       - run: flutter --version