fix: use Float for restore size

[shreddedbacon]

General Checklist

• Affected Issues have been mentioned in the Closing issues section
• Documentation has been written/updated
• PR title is ready for inclusion in changelog

Database Migrations

• If your PR contains a database migation, it MUST be the latest in date order alphabetically

Changes the return type from Int to Float, based on discussion in #3629

Other services in the API that store information related to storage size use Float, and these values would very likely see sizes into the GB if not TB of sizes that a restore would also see.
https://github.com/uselagoon/lagoon/blob/v2.17.0/services/api/src/typeDefs.js#L941
https://github.com/uselagoon/lagoon/blob/v2.17.0/services/api/src/typeDefs.js#L947

Closing issues

closes #3629

[rocketeerbkw]

Tested with a large value 1000000000000000000000000000000000000000000000000000000000000000 and the api returns "restoreSize": 1e+63. This is a number format that javascript can natively use, so it won't error out our current UI implementation. It also corresponds to a file size of 1e+39 YB (yottabytes), which is so large that I couldn't find an example online to compare it to, so it should be fine for file sizes 🤣