Probably not acceptable as is because this would allow executing any snap, not just chromium. And snaps are not guaranteed to be strictly confined (e.g. classic/devmode).
But a rule on /snap/bin/chromium is not good enough as /snap/bin/chromium is a symlink to /usr/bin/snap.
I can "fix" the issue if I add the following two lines to /etc/apparmor. d/abstractions/ ubuntu- browsers and reload the evince profile:
/usr/bin/env rmix,
/usr/bin/snap Cx -> sanitized_helper,
Probably not acceptable as is because this would allow executing any snap, not just chromium. And snaps are not guaranteed to be strictly confined (e.g. classic/devmode).
But a rule on /snap/bin/chromium is not good enough as /snap/bin/chromium is a symlink to /usr/bin/snap.