Updated Documents Function and fixed issued:#769

[Er-Sadiq]

Description This PR introduces the updateDocumentsByFunction method to the Documents class in the Meilisearch SDK. This method enables updating documents in a specified index based on a provided function.

Changes:

Added Method: Implemented the updateDocumentsByFunction method in Documents.java. Allows updating documents using a function via the new /indexes/:uid/documents/edit API endpoint. Includes error handling for null or empty function parameters. Returns a TaskInfo object that provides details about the task created. Addresses issue #769, which requests the addition of document updates via a function.