[pushapkscript] detect existing in-review submission

[jcristau]

Sometimes the play store takes a while to review submissions, and we don't have good mechanisms to detect that beyond someone noticing they don't get updates on their device. We may want to have push-apk detect when previous submissions are sitting in review and optionally abort, to avoid new submissions resetting the review period.

See also:

• Notify release management when push-apk fails mozilla-mobile/focus-android#6720
• Notify release management when push-apk fails mozilla-mobile/fenix#24382
• https://bugzilla.mozilla.org/show_bug.cgi?id=1760570
• https://bugzilla.mozilla.org/show_bug.cgi?id=1628413