fix(fxa-settings): update string id on updated string

[millmason]

Because

• I forgot to update the string id on a string which I changed, so it needs an updated ID to alert localizers to the change.

This pull request

• updates the string id on the changed string.

Issue that this pull request solves

Closes: #12787

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)

N/a (no visible change)

Other information (Optional)

Any other information that is important to this pull request.