Check for helm apps before deleting an environment

[dheeth]

Checklist:

• [x] I've searched in the docs and FAQ for my answer
• [x] I've included steps to reproduce the bug.

Describe the bug

When trying to delete an environment, we get an error if any cd-pipeline exists for the same and if there are no cd-pipelines but helm-apps are there it doesn't check those and environment is deleted which results into dangling helm apps which can't be deleted or updated

To Reproduce

1. Create an environment
2. deploy some devtron-apps as well as helm-apps
3. Try deleting environment
4. If not able to delete, delete all cd-pipelines and then try to delete

Expected behavior

It shouldn't delete if helm-apps deployed using devtron or cd-pipelines are there

Current behavior

It only checks for cd-pipelines and not helm-apps deployed using devtron