Clicking ledger register button breaks add funds button

[luixxiul]

Test Plan:

#8382 (comment)

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Describe the issue you encountered: Clicking ledger register button breaks add funds button.

generate.js:169 Uncaught TypeError: Cannot read property 'forEach' of undefined
    at generateCSS (generate.js:169)
    at injectStyleOnce (inject.js:167)
    at injectAndGetClassName (inject.js:250)
    at css (exports.js:146)
    at BitcoinDashboard.render (bitcoinDashboard.js:344)
    at ReactCompositeComponentWrapper._renderValidatedComponentWithoutOwnerOrContext (ReactCompositeComponent.js:799)
    at ReactCompositeComponentWrapper._renderValidatedComponent (ReactCompositeComponent.js:822)
    at ReactCompositeComponentWrapper.performInitialMount (ReactCompositeComponent.js:362)
    at ReactCompositeComponentWrapper.mountComponent (ReactCompositeComponent.js:258)
    at Object.mountComponent (ReactReconciler.js:46)

• Platform (Win7, 8, 10? macOS? Linux distro?): Windows 10 32bit

• Brave Version (revision SHA): 0.14.2 RC2

• Steps to reproduce:

  1. Open https://jsfiddle.net/LnwtLckc/5/
  2. Click "register" and then choose "Allow"
  3. Open about:preferences#payments
  4. Click "Add funds"

• Expected result: "Transfer BTC" button should be displayed on the modal dialog

• Extra QA steps:
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• Screenshot if needed:

• Any related issues: