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/popover/error_popover.js

@@ -1,7 +1,8 @@
+import React from 'react'
 import PopoverLayout from './popover_layout'
 import ColumnIndicator from '../column_indicator'
 
-export default class ErrorPopover extends PureComponent {
+export default class ErrorPopover extends React.PureComponent {
 
   static defaultProps = {
     isXS: PropTypes.bool,