profile test [nfc]: Rename group about custom fields; pull out some tests

Most of the tests in this group are about custom profile fields.
Pull out the two that aren't, and rename the group.

Author: chrisbobbe

test/widgets/profile_test.dart

@@ -79,18 +79,24 @@ CustomProfileField mkCustomProfileField(
 void main() {
   TestZulipBinding.ensureInitialized();
 
-  group('ProfilePage', () {
-    testWidgets('page builds; profile page renders', (tester) async {
-      final user = eg.user(userId: 1, fullName: 'test user',
-        deliveryEmail: '[email protected]');
+  testWidgets('page builds; profile page renders', (tester) async {
+    final user = eg.user(userId: 1, fullName: 'test user',
+      deliveryEmail: '[email protected]');
 
-      await setupPage(tester, users: [user], pageUserId: user.userId);
+    await setupPage(tester, users: [user], pageUserId: user.userId);
 
-      check(because: 'find user avatar', find.byType(Avatar).evaluate()).length.equals(1);
-      check(because: 'find user name', find.text('test user').evaluate()).isNotEmpty();
-      check(because: 'find user delivery email', find.text('[email protected]').evaluate()).isNotEmpty();
-    });
+    check(because: 'find user avatar', find.byType(Avatar).evaluate()).length.equals(1);
+    check(because: 'find user name', find.text('test user').evaluate()).isNotEmpty();
+    check(because: 'find user delivery email', find.text('[email protected]').evaluate()).isNotEmpty();
+  });
 
+  testWidgets('page builds; error page shows up if data is missing', (tester) async {
+    await setupPage(tester, pageUserId: eg.selfUser.userId + 1989);
+    check(because: 'find no user avatar', find.byType(Avatar).evaluate()).isEmpty();
+    check(because: 'find error icon', find.byIcon(Icons.error).evaluate()).isNotEmpty();
+  });
+
+  group('custom profile fields', () {
     testWidgets('page builds; profile page renders with profileData', (tester) async {
       await setupPage(tester,
         users: [
@@ -153,12 +159,6 @@ void main() {
         .deepEquals([1, 2]);
     });
 
-    testWidgets('page builds; error page shows up if data is missing', (tester) async {
-      await setupPage(tester, pageUserId: eg.selfUser.userId + 1989);
-      check(because: 'find no user avatar', find.byType(Avatar).evaluate()).isEmpty();
-      check(because: 'find error icon', find.byIcon(Icons.error).evaluate()).isNotEmpty();
-    });
-
     testWidgets('page builds; link type will navigate', (tester) async {
       const testUrl = 'http://example/url';
       final user = eg.user(userId: 1, profileData: {