feat: Include statistics for Reserved Fields (#1849)

This is a behavioral change.

In Iceberg-Rust we require upper/lower bounds to be part of the schema.
But in some cases, this isn't the case, for example when you use
reserved fields. In PyIceberg we expect these values in some tests:

```
FAILED tests/integration/test_inspect_table.py::test_inspect_files[2] - AssertionError: Difference in column lower_bounds: {} != {2147483546: b's3://warehouse/default/table_metadata_files/data/00000-0-8d621c18-079b-4217-afd8-559ce216e875.parquet', 2147483545: b'\x00\x00\x00\x00\x00\x00\x00\x00'}
assert {} == {2147483545: ...e875.parquet'}
  Right contains 2 more items:
  {2147483545: b'\x00\x00\x00\x00\x00\x00\x00\x00',
   2147483546: b's3://warehouse/default/table_metadata_files/data/00000-0-8d621c1'
               b'8-079b-4217-afd8-559ce216e875.parquet'}
  Full diff:
    {
  +  ,
  -  2147483545: b'\x00\x00\x00\x00\x00\x00\x00\x00',
  -  2147483546: b's3://warehouse/default/table_metadata_files/data/00000-0-8d621c1'
  -              b'8-079b-4217-afd8-559ce216e875.parquet',
    }
!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!
==== 1 failed, 238 passed, 32 skipped, 3123 deselected in 61.56s (0:01:01) =====
```

This is a positional delete where the field-IDs are constant, but never
part of a schema (they are reserved).

## Which issue does this PR close?


- Closes #.

## What changes are included in this PR?



## Are these changes tested?



---------

Co-authored-by: Kevin Liu <kevinjqliu@users.noreply.github.com>
Co-authored-by: Renjie Liu <liurenjie2008@gmail.com>

Author: 3 people