[Streams] - UI shows that only one stage can be added to the stream

[apandura-tibco]

Environment

How are you running Flogo Web?

• Docker (Specify the docker image that you're using and the command you used to start the container)
• Other (Provide details of your environment) : Local development environment in Windows.

Describe the bug

The streams page is showing that only one stage can be added to the stream.

To Reproduce

Steps to reproduce the behavior:

1. Open stream's designer page
2. Change the configuration of an existing stage and save the configuration
3. hover on the row to add new stage
4. Notice that I see only one place holder for adding a stage

Include error logs if applicable.

Expected behavior

I should always be able to see the remaining place holders available to add a stage