[xcm-emulator] Improve hygiene and clean up (#1301)

* improve hygiene & clean up

* improve hygiene & clean up - xcm-emulator

* improve hygiene & clean up - common

* improve hygiene & clean up - tests

* improve hygiene & clean up - tests 2

* last hygiene bits

* ".git/.scripts/commands/fmt/fmt.sh"

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Co-authored-by: command-bot <>