[FEA] Support `num_rows_per_source` in table metadata after a `cudf::io::read_json`

**Is your feature request related to a problem? Please describe.**
After doing a `read_json` call, I'd like to be able to get the number of rows in each source in the output tables metadata. Eg.
```python
import pylibcudf as plc

df = plc.io.json.read_json(
plc.io.json.JsonReaderOptions.builder(
plc.io.types.SourceInfo(["df.json"])
).lines(True).build()
)

print(df.num_rows_per_source)
```
```
[]
```
Right now the list is empty.

**Describe the solution you'd like**
Populate this field in the libcudf implementation.

**Additional context**
xref #18057 (polars feature that needs this)