[SPARK-39054][PYTHON][PS] Ensure infer schema accuracy in GroupBy.apply

[Yikun]

What changes were proposed in this pull request?

Ensure sampling rows >= 2 to make sure apply's infer schema is accurate.

Why are the changes needed?

GroupBy.apply infers schema when the type hints is not specified for the func of grouby.apply. We cannot guarantee that the infer schema of the sampled values ​​is completely accurate, but we should make it as accurate as possible.

Since v1.4, Pandas introduce an interface change [1], especially it has some impact the behavior of Group.apply when df has single row (head(1)):

>> psdf
Out[9]: 
  __groupkey_0__  timestamp car_id
0              A        0.0      A
1              A        0.0      A

>> psdf.head(1)._to_internal_pandas().groupby(groupkeys).apply(pandas_apply, *args, **kwargs)

Out[10]: 
   column
0     0.0

>> psdf.head(2)._to_internal_pandas().groupby(groupkeys).apply(pandas_apply, *args, **kwargs)

Out[11]: 
          column
car_id          
A      0     0.0

Finally, it causes the mismatch error of sample apply infer schema and final apply results.

[1] https://pandas.pydata.org/pandas-docs/stable/whatsnew/v1.4.0.html#groupby-apply-consistent-transform-detection

Does this PR introduce any user-facing change?

No

How was this patch tested?

• GA CI passed
• test_apply_infer_schema_without_shortcut and test_apply_with_new_dataframe_without_shortcut passed with v1.4.

[HyukjinKwon]

Merged to master.