"There are no eligible environments" for Non-production pipeline

### Expected Behaviour

For the exercise 4 - Deploy Your First Project to AEM Cloud, item 2 [Create a Non-Production Deployment Pipeline](https://github.com/adobe/aem-enablement/tree/master/AEMAsACloudService/04_Deploy_Custom_Project#step-2-create-a-non-production-deployment-pipeline), it is expected to be able to create the pipeline.

### Actual Behaviour

When using Adobe provided Sandbox, after selecting Deployment Pipeline, we get the "There are no eligible environments" message below.


That is probably because there is already a Non-prod pipeline provided for the sandbox environment. So the recommendation is to update the text in the exercise to verify if there is a non-prod pipeline already.

### Reproduce Scenario (including but not limited to)

N/A

#### Steps to Reproduce

Same steps as indicated in [4 - Deploy Your First Project to AEM Cloud](https://github.com/adobe/aem-enablement/tree/master/AEMAsACloudService/04_Deploy_Custom_Project#deploy-your-first-project-to-aem-cloud)

#### Platform and Version

AEM Release 2021.9.5852.20210917T073206Z

#### Sample Code that illustrates the problem

N/A

#### Logs taken while reproducing problem

N/A

Start with AEMAsACloudService/04_Deploy_Custom_Project and read the “Create a Non-Production Deployment Pipeline” section linked in the issue. Update the exercise text to tell learners to check whether a non-production pipeline already exists before creating one; done means the instructions match the Adobe Sandbox behavior described here.

Written by the indexing model from the issue text.