fix: use Float for restore size

[shreddedbacon]

General Checklist

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

Database Migrations

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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