Phases are ignored on push

[schlamar]

Consider a history like this

* [draft]  commit-to-be-pushed
|
x [public] ...
|
|  * [secret] commit not to be pushed
 /
|
x [public]

With standard hg, you can push this without any issue. However, vscode-hg is ignoring the secret phase and gives me a warning about multiple heads and that I should merge before pushing.