fix(specs): change fileSize to int64 type (#4877)

## 🧭 What and Why

🎟 JIRA Ticket: [DI-3831](https://algolia.atlassian.net/browse/DI-3831)

Fixes algolia/algoliasearch-client-go#771

Author: millotp

specs/search/common/schemas/listIndicesResponse.yml

@@ -34,10 +34,12 @@ fetchedIndex:
       example: 100
     dataSize:
       type: integer
+      format: int64
       description: Number of bytes of the index in minified format.
       example: 48450
     fileSize:
       type: integer
+      format: int64
       description: Number of bytes of the index binary file.
       example: 112927
     lastBuildTimeS: