Fix: abstract EventLoop::Polling#system_add invalid signature

[straight-shoota]

Resolves #15357

[ysbaddaden]

Oh my 🤦

[github-actions]

Successfully created backport PR for release/1.15:

• [Backport release/1.15] Fix: abstract EventLoop::Polling#system_add invalid signature #15380

[crysbot]

Backport failed for release/1.15, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin release/1.15
git worktree add -d .worktree/backport-15358-to-release/1.15 origin/release/1.15
cd .worktree/backport-15358-to-release/1.15
git switch --create backport-15358-to-release/1.15
git cherry-pick -x 5a245d905717ff9ea8a62512d8a5e0fefa721959