Bug: ScaffoldTask doesn't follow the new metadata format

[jormundur00]

Describe the bug

ScaffoldTask still works with the old config files (such as reflect-config.json), when it should be working with the new reachability-metadata.json format.

Steps to reproduce

Run `./gradlew scaffold -Pcoordinates=<coordinates>`

Expected behavior

It should generate the new reachability-metadata.json, while not parsing the old file format.

Logs and error messages

N/A

Reproducer (optional)

No response

Additional context

No response

GraalVM version

GraalVM 25.0.2

Operating system

Linux

CPU architecture

AMD64 (x86-64)