Use globally-available reCAPTCHA source

What does this MR do?

Use a globally-available reCAPTCHA source. As google.com is blocked in some countries, use recaptcha.net to get the client-side JavaScript source instead. This is recommended by the reCAPTCHA FAQ in order to make it available to users in all countries.

What are the relevant issue numbers?

Fixes #56375 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer