push: remote configured with `worktree = true` pushes imports

[dberenbaum]

Bug Report

Description

Pushes data imported with dvc import to remote when remote is configured with worktree = true.

Reproduce

1. Clone https://github.com/iterative/example-get-started
2. Configure a remote with worktree = true
3. Push to that remote
4. Check that data/data.xml was pushed

Expected

data/data.xml is imported from a data registry and should not be pushed.