🧹 Fix ignored error for DataUsageInfo in BucketsHandler

[damacus]

🎯 What: Handled the previously ignored error from mdm.DataUsageInfo(c.Request().Context()) in internal/handlers/buckets_handler.go.
💡 Why: Silently ignoring errors is poor practice. Logging the error improves visibility and helps debugging when users lack sufficient admin permissions to fetch data usage. Since the code handles a nil or empty BucketSizes properly when falling back to 0, it's safer to just log this specific error rather than throw an HTTP 500 block for users who only have bucket listing permissions, not global permissions.
✅ Verification: Ran go test ./... in the background utilizing automatic downloading, ensuring existing functionality tests pass. Verified the refactored chunk avoids shadowing scope and continues execution when the error triggers.
✨ Result: Better error visibility, improved maintainability of the handlers package.

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PR created automatically by Jules for task 9830336635236494968 started by @damacus

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