[samples_index] updated source code url for form_app (#688)

experimental/desktop_photo_search/lib/src/widgets/about_dialog.dart

@@ -45,7 +45,9 @@ class PolicyDialog extends StatelessWidget {
                     children: <TextSpan>[
                       TextSpan(
                         text: 'https://policies.google.com/terms',
-                        style: TextStyle(fontWeight: FontWeight.bold, color: Colors.lightBlue),
+                        style: TextStyle(
+                            fontWeight: FontWeight.bold,
+                            color: Colors.lightBlue),
                         recognizer: TapGestureRecognizer()
                           ..onTap = () async {
                             final url = 'https://policies.google.com/terms';
@@ -65,7 +67,9 @@ class PolicyDialog extends StatelessWidget {
                     children: <TextSpan>[
                       TextSpan(
                         text: 'https://unsplash.com/terms',
-                        style: TextStyle(fontWeight: FontWeight.bold, color: Colors.lightBlue),
+                        style: TextStyle(
+                            fontWeight: FontWeight.bold,
+                            color: Colors.lightBlue),
                         recognizer: TapGestureRecognizer()
                           ..onTap = () async {
                             final url = 'https://unsplash.com/terms';

web/samples_index/lib/src/samples.yaml

@@ -348,7 +348,7 @@ samples:
         alt: Form App screenshot
       - url: images/form_app3.png
         alt: Form App screenshot
-    source: https://github.com/flutter/samples/tree/master/experimental/form_app
+    source: https://github.com/flutter/samples/tree/master/form_app
     description: >
       A Flutter sample app that shows how to use Forms.
     difficulty: intermediate

web/samples_index/pubspec.yaml

@@ -24,4 +24,3 @@ dev_dependencies:
   build_web_compilers: ^2.7.0
   tuneup: ^0.3.6
   image: ^2.1.0
-