Fix projection name with DataFrame::with_column and window functions

[devanbenz]

Signed-off-by: Devan devandbenz@gmail.com## Which issue does this PR close?

Closes#11982

Rationale for this change

Previous usage of dataframe with_column using a Window expression was causing an unnecessary projection in the output.

+---+-----------------------------------------------------------------------+---+
| a | ROW_NUMBER() ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING | r |
+---+-----------------------------------------------------------------------+---+
| 1 | 1 | 1 |
| 2 | 2 | 2 |
| 3 | 3 | 3 |
| 4 | 4 | 4 |
| 5 | 5 | 5 |
+---+-----------------------------------------------------------------------+---+

I also tested manually with a few other Expr to test if that would cause issues by filtering the qualifier:

 let func = Expr::Literal(ScalarValue::Int32(Some(10)));
df.with_column("r", func)?.show().await?;

outputs:

+---+----+
| a | r |
+---+----+
| 5 | 10 |
| 4 | 10 |
| 3 | 10 |
| 2 | 10 |
| 1 | 10 |
+---+----+

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

[alamb]

Looks good to me -- thank you @devanbenz

cc @timsaucer thank you for the report. Perhaps you have time to review the change as well

[alamb]

I think you can use the expr fn here and make this more concise:

Suggested change

	let func = Expr::WindowFunction(WindowFunction::new(
	WindowFunctionDefinition::BuiltInWindowFunction(
	BuiltInWindowFunction::RowNumber,
	),
	vec![],
	))
	.alias("row_num");
	let func = row_number().alias("row_num");

[alamb]

I also ran this test without the code changes and it fails like this:

assertion `left == right` failed
left: 4
right: 5
Left: 4
Right: 5
<Click to see difference>
thread 'dataframe::tests::test_window_function_with_column' panicked at datafusion/core/src/dataframe/mod.rs:2882:9:
assertion `left == right` failed
left: 4
right: 5
stack backtrace:
0: rust_begin_unwind
at /rustc/3f5fd8dd41153bc5fdca9427e9e05be2c767ba23/library/std/src/panicking.rs:652:5
...

And the output was like

[
"+----+----+-----+-----------------------------------------------------------------------+---+",
"| c1 | c2 | c3 | ROW_NUMBER() ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING | r |",
"+----+----+-----+-----------------------------------------------------------------------+---+",
"| c | 2 | 1 | 1 | 1 |",
"| d | 5 | -40 | 2 | 2 |",
"+----+----+-----+-----------------------------------------------------------------------+---+",
]

[devanbenz]

Sounds good I went ahead and used the more concise method call. Thanks!

[timsaucer]

LGTM. I also tested locally and it produces the expected results. Thank you for taking care of this!

[alamb]

Thanks again @devanbenz and @timsaucer -- getting better every day!