[ews] Parameterize email based on uat vs prod.
<rdar://problem/103138631>
Pull request: https://github.com/WebKit/WebKit/pull/7333
Committed 257579@main (71f9e554f9a2): <https://commits.webkit.org/257579@main> Reviewed commits have been landed. Closing PR #7333 and removing active labels.