Fixed contribution statement display

[bsclifton]

Test plan

#7699 (comment)

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• Did you search for similar issues before submitting this one?
  yes

• Describe the issue you encountered:

If you have a contribution history with Brave Payments and go to the Payments tab of preferences, you'll be able to see your previous statements. If you click one, you'll notice that a new tab opens which has your statement. It then closes really fast

The saving bug was fixed with #7416, but it would still be nice to view the statement in browser.

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

• Brave Version (revision SHA):
  0.13.5

• Steps to reproduce:
  1.
  2.
  3.

• Actual result:
  Tab with statement auto closes

• Expected result:
  Tab stays open

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  No- you need a contribution history. You can generate that using an npm run command

• Is this an issue in the currently released version?
  yes

• Can this issue be consistently reproduced?

• Extra QA steps:
  1.
  2.
  3.

• Screenshot if needed:

• Any related issues:

[diracdeltas]

related: #2714