Fix the top margin of a button in a form (#5461)

* remove where

* add example to cra

* update example in cra

Author: yihuiliao

examples/rsp-cra-18/src/App.tsx

@@ -1,5 +1,5 @@
 import './App.css';
-import {Provider, defaultTheme, Item, TagGroup, Cell, Column, Row, TableBody, TableHeader, TableView, Content, Heading} from '@adobe/react-spectrum';
+import {Provider, defaultTheme, Item, TagGroup, Cell, Column, Row, TableBody, TableHeader, TableView, Content, Heading, Form, ComboBox, Button} from '@adobe/react-spectrum';
 import Lighting from './Lighting';
 import {useState} from 'react'
 import BodyContent from './BodyContent';
@@ -27,8 +27,7 @@ function App() {
 
   return (
     <Provider theme={defaultTheme}
-              colorScheme={selected ? "light" : "dark"}
-              height="100%">
+              colorScheme={selected ? "light" : "dark"}>
       <div className="content-padding">
         <Lighting selected={selected} switch={setSelection}/>
         <TagGroup aria-label="Static TagGroup items example">
@@ -56,6 +55,17 @@ function App() {
           <Heading>Payment Information</Heading>
           <Content>Enter your billing address, shipping address, and payment method to complete your purchase.</Content>
         </InlineAlert>
+        <Form width="250px">
+          <ComboBox label="Favorite Animal">
+            <Item key="red panda">Red Panda</Item>
+            <Item key="cat">Cat</Item>
+            <Item key="dog">Dog</Item>
+            <Item key="aardvark">Aardvark</Item>
+            <Item key="kangaroo">Kangaroo</Item>
+            <Item key="snake">Snake</Item>
+          </ComboBox>
+          <Button variant="cta">Click Me</Button>
+        </Form>
       </div>
     </Provider>
   );

packages/@adobe/spectrum-css-temp/components/fieldlabel/index.css

@@ -196,7 +196,7 @@ governing permissions and limitations under the License.
   }
 
   /* With labelPosition=top, we use a normal flex stack */
-  &:where(.spectrum-Form--positionTop) {
+  &.spectrum-Form--positionTop {
     display: flex;
     flex-direction: column;
     margin: 0;