Direct download template size is incorrect

### problem

Direct download template size is incorrect

### versions

ACS 4.22.1

### The steps to reproduce the bug

1. Create a metalink file

Example
```

10485760

nfs://10.0.35.201/export/templates/ubuntu24-cloud-image-root-password-with-tools.qcow2

```

2. Expose it via http server

python3 -m http.server 8081 --bind 0.0.0.0

3. Register it a direct download template in cloudstack

4. Check the size

...

### What to do about it?

The correct size of the direct download template should be displayed

Reproduce the issue by registering the provided metalink as a direct download template in CloudStack and checking the displayed size. Trace the direct-download template registration and size-display entry points, then verify that the displayed size matches the metalink's declared value.

Written by the indexing model from the issue text.