feat(ui): add invoices button, format snapshot error (platform#242)

Description

• In Billing, let's add a button "Invoices", under the right column with payment methods -- and it should act exactly the same as "Payment methods" (opening stripe's customer portal; invoices are there).
• Reduce payment methods section width
• Format snapshot error, so that UI only renders message

Related issue

https://gitlab.com/postgres-ai/platform/-/issues/242

Examples

Updated billing page

Updated snapshot error message

Checklist

• MR description has been reviewed
• MR changes are functionally tested
• MR does NOT have API/CLI changes OR there are API/CLI changes and they have been reviewed & DOCS ARE ADJUSTED (reference doc, etc)
• MR does NOT have UI changes OR there are UI changes and they have been reviewed & UX IS REVIEWED