Remove React, PureComponent global import, added those imports to files directly

• Remove:
- React, PureComponent global import and added those imports to files directly

app/javascript/gabsocial/components/sidebar_section_title.js

@@ -1,6 +1,7 @@
+import React from 'react'
 import Text from './text'
 
-export default class SidebarSectionTitle extends PureComponent {
+export default class SidebarSectionTitle extends React.PureComponent {
 
   static propTypes = {
     children: PropTypes.string.isRequired,