Update details for multiple group locations

Updates detail fields for one or more locations within a group in a single call, designed for bulk ingestion workflows where location data arrives as a batch from an external roster or source system. Each entry targets a specific location; this is a partial merge per location entry, not a full replace — omitted fields are preserved from the existing record rather than cleared. Use this endpoint when updating multiple locations at once; to add a new location to a group use POST /groups/{groupId}/locations.