Only steps for on phase are included

[fhanggi]

Installed product versions

• Export/Import Buid Definition extension: 0.0.8

Description

We are using TFS 2018 Update 3 on premise (16.131.28226.3)

I wanted to exporte a build definition that contains 3 phases. However the exported file only contains the first phase

Steps to recreate

1. Create a build with multiple phases
2. Export
3. Open json file. You will only see the first phase in the exported file

Expected behavior

All phases should be included in the exported file.