fix(fxa-payments-server): capture productId with PayPal payments

[caugner]

Because

• PayPal payments events were not capturing the Product ID of the selected Plan.

This pull request

• Makes sure that the Product ID is captured for PayPal payments.

Issue that this pull request solves

Closes: #12432

Checklist

Put an x in the boxes that apply

• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
• I have verified that my changes render correctly in RTL (if appropriate).

Screenshots (Optional)

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Other information (Optional)

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[caugner]

FWIW The failed check is unrelated:

/bin/bash: CIRCLE_TOKEN: Please provide a CircleCI API token for this orb to work!

[StaberindeZA]

@caugner Thank you for the change. I had a quick look at the code and it looks good.

There are just a few small things I was hoping you could address. I've listed them below.

• Could you please squash your commits so that there's only 1 commit with all changes?
• Regarding the commit message, could you please review the contribution guidelines found here. At the moment the commits are missing a body.
• Finally, to get the Circle CI tests to pass, could you please create a new PR and push your changes directly to mozilla/fxa instead of your fork. We had a similar situation with a first time contributor recently. (Here's their PR for reference)

[caugner]

Finally, to get the Circle CI tests to pass, could you please create a new PR and push your changes directly to mozilla/fxa instead of your fork. We had a similar situation with a first time contributor recently.

@StaberindeZA How do I get push access to this repository?

ERROR: Permission to mozilla/fxa.git denied to caugner.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Edit: Probably it would be good to update CONTRIBUTING.md with the new contribution instructions. That document has some dead links, mentions npm and grunt as well as forking, but not squashing.

[caugner]

@StaberindeZA I have now squashed, and updated the commit message according to the contribution guidelines.

[biancadanforth]

LGTM and CI passed thanks to Barry's DNM PR. Thank you Claas for the patch.

[caugner]

@annasob Have these changes already landed on production? Asking, because I'm not yet seeing a productId on PayPal subscription events (https://mozilla.cloud.looker.com/dashboards/596).

[annasob]

Train 231 will be deployed tomorrow starting at 1pm EST