Use common.Hash to generate UUID instead of Gob.

Goal: Current Hash of UUID does not look like hash.
Priority: Very Low

Currently using gob.NewEncoder to generated a UUID from RunIdentifier.
[Link](https://github.com/Fantom-foundation/Aida/blob/d012bb311a7143cac36ecfa3f83f44d4a732c113/executor/extension/register/identifier.go#L34C2-L34C21)

This should use common.Hash so that the generated UUID aligns with existing format.