source-google-ads: upgrade off of API version v19

[Alex-Bair]

source-google-ads is currently using v19 of the Google Ads API, which is deprecated and will stop accepting requests on 11FEB2026. We need to upgrade to a newer API version to avoid disruptions for source-google-ads captures. Unless there's a major breaking change, we should consider upgrading to the most recent API version v22.

[Alex-Bair]

For reference during implementation, here's a PR where we performed a similar API version upgrade from v17 to v19.