[cmake] Remove Applications symlink in the OSX zip

Summary: This is a relic from the time we had a dmg, it's no longer used.

Test Plan:
Run the OSX guix build.
Unzip the archive and check the symlink is no longer here.

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D18935