BUG: Polars DataFrameModel.validate crashes with sample specified

[m-richards]

Describe the bug
A clear and concise description of what the bug is.

• I have checked that this issue has not already been reported.
• I have confirmed this bug exists on the latest version of pandera.
• (optional) I have confirmed this bug exists on the main branch of pandera.

Code Sample, a copy-pastable example

import pandera.polars as pa

import pandas as pd
import polars as pl

from pandera.typing import Series


class SchemaPolars(pa.DataFrameModel):
    col1: Series[int]
    col2: Series[int]

pandas_df = pd.DataFrame({"col1": [1, 2, 3], "col2": [1, 2, 3]})
polars_df = pl.from_pandas(pandas_df)

result2 = SchemaPolars.validate(polars_df, sample=10)
Traceback (most recent call last):
  File "C:\Data\myDocuments\Code\python_other\pandera\fork\tester_sample.py", line 24, in <module>
    result2 = SchemaPolars.validate(lazyframe, sample=10)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Data\myDocuments\Code\python_other\pandera\fork\pandera\api\dataframe\model.py", line 289, in validate
    cls.to_schema().validate(
  File "C:\Data\myDocuments\Code\python_other\pandera\fork\pandera\api\polars\container.py", line 64, in validate
    output = self.get_backend(check_obj).validate(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Data\myDocuments\Code\python_other\pandera\fork\pandera\backends\polars\container.py", line 80, in validate
    sample = self.subsample(check_obj, head, tail, sample, random_state)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Data\myDocuments\Code\python_other\pandera\fork\pandera\backends\polars\base.py", line 50, in subsample
    check_obj.sample(sample, random_state=random_state)
    ^^^^^^^^^^^^^^^^
AttributeError: 'LazyFrame' object has no attribute 'sample'

Expected behavior

Sample should work, or should raise a NotImplementedError if not supported.

Desktop (please complete the following information):

• OS: Windows 11, using python 3.12.8

Additional context

I came across this looking at running mypy over pandera.
The implementation calls .sample which is a pl.DataFrame method, but there is no lazy equivalent.

pola-rs/polars#3933 discusses this with some potential workarounds listed, e.g.
lazy_df.with_row_index().filter(col("index").hash(seed)%10 == 1).drop("index")

[cosmicBboy]

thanks for finding this @m-richards ! yes this should only work with pl.DataFrame and raise a NotImplementedError with pl.LazyFrame