Drag and dropping a core pipeline doesn't work when block_source is missing for one of the blocks.

[FGRCL]

Summary:

When dropping a pipeline from the core library into the canvas. The block_source of all blocks have to be specified, otherwise it won't load properly. However, loading through the load pipeline button works.

Expected behavior:

The core pipeline should simply be copied, as with the load pipeline flow.

Actual behavior:

The pipeline fails to load

Steps to reproduce:

1. Add a pipeline to the core library
2. Remove the block_source for one of the blocks
3. Drop it in the canvas
4. Witness that it fails to load

Zetaforge version:

0.2.1

Operating System

Windows

Other operating system:

All

Logs:

Not recorded

Recording:

No response

Anything else?:

No response