Frontend: Input and output labels inside the Subgraph be rearrangeable.

### Feature Idea

Currently once linked are connected inside a subgraph there is no way to rearrange the labels like moving one up or down. Since these labels (input or output) are in fact important in the main graph where subgraph appears just a node, the rearrangement makes a lot of sense to correct connections so to match other nodes. This way the resulting linkage can be more pleasing.

### Existing Solutions

_No response_

### Other

_No response_