fix slot underflow in `check_consensus_slot_range` task #154

Job	Run time
Run code checks / Run code checks	55s
Generate project documentation	4s
Build Assertoor / Build linux/arm64 binary	1m 37s
Build Assertoor / Build macos/arm64 binary	1m 21s
Build Assertoor / Build linux/amd64 binary	30s
Build Assertoor / Build macos/amd64 binary	1m 7s
Build Assertoor / Build windows/amd64 binary	4m 40s
Build Assertoor / Build amd64 docker image	21s
Build Assertoor / Build arm64 docker image	1m 43s
Build Assertoor / Build multiarch docker image	7s
Build Assertoor / Build additional docker manifests (master)	19s
Build Assertoor / Build additional docker manifests (master-latest)	18s
Create snapshot release	20s
	13m 22s

Provide feedback