pipeline.draw() does not show user-provided value to variadic input

[Willenbrink]

Describe the bug
Providing run with a value to a variadic input, e.g. a branchJoiner, is not shown by pipeline.draw().

Additional context
As a result, the branchJoiner that should sit at the top of the pipeline is instead shown at the very bottom, making the structure a bit confusing.
This is probably intentional for optional inputs but variadic inputs should be handled separately IMHO as they are relevant to the control flow.

To Reproduce

• Create a pipeline with a loop using branchJoiner
• Provide it with a value through a connection and through run({"branchJoiner": { "value": value}})
• Call pipeline.draw()
• See the node appearing at the bottom of the pipeline instead of at the top. The user provided input, normally shown with a star, does not point to the branchJoiner node.

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System:

• OS: Linux
• Haystack version (commit or version number): 2.7.0