SKUs SDK Changes to Support Receipt Submission

[husobee]

Implementation of generic receipt submission client for SKUs SDK, including WASM bindings which will support various vendor (google, apple) payment confirmations for in-app purchases.

Resolves https://github.com/brave/brave-browser/issues/23167 Security / privacy review: https://github.com/brave/security/issues/933

Submitter Checklist:

• [x] I confirm that no security/privacy review is needed, or that I have requested one
• [x] There is a ticket for my issue
• [x] Used Github auto-closing keywords in the PR description above
• [x] Wrote a good PR/commit description
• [x] Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• [ ] Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• [x] Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• [ ] Ran git rebase master (if needed)

Reviewer Checklist:

• [ ] A security review is not needed, or a link to one is included in the PR description
• [ ] New files have MPL-2.0 license header
• [ ] Adequate test coverage exists to prevent regressions
• [ ] Major classes, functions and non-trivial code blocks are well-commented
• [ ] Changes in component dependencies are properly reflected in gn
• [ ] Code follows the style guide
• [ ] Test plan is specified in PR before merging

After-merge Checklist:

• [ ] The associated issue milestone is set to the smallest version that the changes has landed on
• [ ] All relevant documentation has been updated, for instance:
  • [ ] https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • [ ] https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • [ ] https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • [ ] https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • [ ] https://github.com/brave/brave-browser/wiki/Custom-Headers
  • [ ] https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • [ ] https://github.com/brave/brave-browser/wiki/QA-Guide
  • [ ] https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

[bsclifton]

We don't have an integration using this... yet! But https://github.com/brave/brave-core/pull/13387 will definitely be using this code 😄 See more details in https://github.com/brave/security/issues/933#issuecomment-1169200217

Code LGTM - but would leave to @evq or another person to review also (since I helped 😄). @husobee there were some comments by @spylogsster in case you missed them above

[evq]

I don't love all the repeated mangling we're doing at the moment to convert errors into something that wasm-bindgen is happy with, I think we should look into whether the resolution linked at the bottom of this issue helps clean things up [1]

[1] https://github.com/rustwasm/wasm-bindgen/issues/1004