Fix type of shard_id

[flobernd]

As titled.

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
search	🔴	2316/2401	2384/2385
snapshot.cleanup_repository	🟢	3/3	3/3
snapshot.clone	🟢	5/5	5/5
snapshot.create_repository	🔴	24/29	29/29
snapshot.create	🟢	29/29	29/29
snapshot.delete_repository	🟢	10/10	10/10
snapshot.delete	🔴	21/23	23/23
snapshot.get_repository	🔴	19/19	7/19
snapshot.get	🟢	13/13	13/13
snapshot.repository_analyze	⚪	Missing test	Missing test
snapshot.repository_verify_integrity	⚪	Missing test	Missing test
snapshot.restore	🟢	5/5	5/5
snapshot.status	🟢	2/2	2/2
snapshot.verify_repository	🟢	2/2	2/2

You can validate these APIs yourself by using the make validate target.