Issue #124969 by Dave Reid, andregp, naxoc, pameeela, ravi.shankar,...

Issue #124969 by Dave Reid, andregp, naxoc, pameeela, ravi.shankar, bruno.bicudo, _pratik_, jnlar, yogeshmpawar, marcingy, StevenPatz, amitgoyal, Johnny Santos, larowlan, smustgrave, Dries, DanielVeza, mstrelan, cburschka, quietone, alexpott, bradlis7: Contact form opt-out line should be excluded from admin-sent and sender-copy e-mails

(cherry picked from commit 1dbf2cc2)