[FEATURE] Email and HTTP trigger created in Workflow builder should appear on Sources page and reusable in other workflows

**Is your feature request related to a problem? Please describe.**
Currently, Email and HTTP trigger created in Workflow builder:
1. Does not have matching source appeared in Sources page, and
2. Can not be reused in other workflows

Steps to reproduce:
1. Create a new workflow, add an HTTP trigger
2. Go to [Sources page](https://pipedream.com/sources)
3. Observe that the created trigger does not have a matching source

**Describe the solution you'd like**
The Email and HTTP trigger should be shown in the Sources page and can be reused in other workflows

**Do you have a workaround?**
No

**Additional context**
A customer want to migrate their old v1 workflow to v3 workflow, but their v1 workflow contains an Email trigger that can not be reused in the V3 workflow