fix(frontend): missing import (#12029)

Fix missing import 
Unified use of spaces in import statements

Author: constantinius

develop-docs/frontend/using-styled-components.mdx

@@ -112,6 +112,7 @@ The `style` and `css` attributes can be used, but the values of `style` are not
 ```tsx
 import styled from '@emotion/styled';
 import {css} from '@emotion/react';
+import {space} from 'sentry/styles/space';
 
 // ✅ Don't be afraid of inline styles for one-off values
 const Grid = styled('div')`