[GadiVenkatesh]

Summary

• Preserve the original value type when converting objects into JMeter properties.
• Enable the existing MapProperty integer-type regression test.
• Add CollectionProperty regression coverage because both use the shared conversion logic.

Root cause

AbstractProperty.convertObject() uses the container's property type when converting raw values. During initialization, this can fall back to StringProperty instead of preserving the original integer type.

Testing

• Added regression coverage for integer values in MapProperty and CollectionProperty.
• Tests have not yet been run locally; CI validation is required.

Fixes #6830