Fix compiler errors

Author: Rokt33r

src/components/App.tsx

@@ -1,12 +1,11 @@
-import React, { useMemo, useState, useEffect } from 'react'
+import React, { useState, useEffect } from 'react'
 import Router from './Router'
 import GlobalStyle from './GlobalStyle'
 import { ThemeProvider } from 'styled-components'
 import { selectTheme } from '../themes'
 import Dialog from './organisms/Dialog'
 import { useDb } from '../lib/db'
 import PreferencesModal from './PreferencesModal/PreferencesModal'
-import { useGlobalKeyDownHandler, isWithGeneralCtrlKey } from '../lib/keyboard'
 import { usePreferences } from '../lib/preferences'
 import '../lib/i18n'
 import '../lib/analytics'

src/mobile/components/organisms/PreferencesModal.tsx

@@ -13,7 +13,6 @@ import ExternalLinkTableViewCell from '../atoms/ExternalLinkTableViewCell'
 import MobilePageContainer from '../atoms/MobilePageContainer'
 import GeneralPreferencesTab from './GeneralPreferencesTab'
 import EditorPreferencesTab from './EditorPreferencesTab'
-import BillingTab from '../../../components/PreferencesModal/BillingTab'
 
 const PreferencesModalContainer = styled.div`
   z-index: 7000;
@@ -117,8 +116,6 @@ function getTab(tab: 'general' | 'editor' | 'billing') {
   switch (tab) {
     case 'editor':
       return <EditorPreferencesTab />
-    case 'billing':
-      return <BillingTab />
     default:
     case 'general':
       return <GeneralPreferencesTab />