Batch delete expects an array of Int for document id (even though string document ids are also valid)

[aronbudinszky]

Description
Batch deletion from index expects an array of int for document ID even though said ID can be any valid String, such as a UUID for example.

Expected behavior
Batch deletion should work similar to single deletion - it should accept strings of any kind.

Environment (please complete the following information):

• OS: Ubuntu 22.04
• Meilisearch version: 0.28
• meilisearch-swift version: 0.14.1