Brave Payments FAQ link is not obvious

[cndouglas]

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

• Describe the issue you encountered:
  The View the FAQ link in Preferences > Payments is not obvious because it is neither underlined nor colored.

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

• Brave Version (revision SHA):
  0.13.5 (1db81cb)

• Steps to reproduce:

  1. Open Preferences > Payments
  2. Disable Payments if needed.
  3. Look at the View the FAQ text and wonder if it's a link…

• Actual result:
  The link appears like normal text.

• Expected result:
  The link should be underlined and colored orange like other links.

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  Probably.

• Is this an issue in the currently released version?
  Yes, 0.13.5.

• Can this issue be consistently reproduced?
  Yes.

• Extra QA steps:

  1. Open Preferences > Payments
  2. Disable Payments if needed.
  3. Look at the View the FAQ text and make sure it looks like a link.

• Screenshot if needed:
  
  Compare to Preferences > Plugins:
  

• Any related issues:
  Localization of Payments FAQ text on about:payments #4102

[cndouglas]

I'm not sure why link underline is disabled in Payment preferences here: https://github.com/brave/browser-laptop/blob/master/less/about/preferences.less#L311

Regardless, I can still color the link by adding the linkText class name.