Accept a response code of 206 from Uphold cards endpoint (uplift to 1.62.x)

[brave-builds]

Uplift of #21647
Resolves brave/brave-browser#35445

Pre-approval checklist:

• You have tested your change on Nightly.
• This contains text which needs to be translated.
  • There are more than 7 days before the release.
  • I've notified folks in #l10n on Slack that translations are needed.
• The PR milestones match the branch they are landing to.

Pre-merge checklist:

• You have checked CI and the builds, lint, and tests all pass or are not related to your PR.

Post-merge checklist:

• The associated issue milestone is set to the smallest version that the changes is landed on.

[Miyayes]

No longer needed as Uphold API change is being delayed. More context available via https://bravesoftware.slack.com/archives/CB0KCRCQN/p1705600861828419.