DataFrame Merge method throws exception when one of the DataFrames is empty.

[sevenzees]

System Information (please complete the following information):

• OS & Version: All
• ML.NET Version: 5.0.0
• .NET Version: 8

Describe the bug
When using the DataFrame Merge method, if one of the DataFrames is empty (has no rows), you will get a System.ArgumentOutOfRangeException.

To Reproduce
This code will reproduce the behavior:
DataFrame left = new DataFrame(
new Int32DataFrameColumn("Index"),
new Int32DataFrameColumn("L1"),
new Int32DataFrameColumn("L2"),
new StringDataFrameColumn("L3")
);
DataFrame right = new DataFrame(
new Int32DataFrameColumn("Index", new[] { 0, 1, 2 }),
new Int32DataFrameColumn("R1", new[] { 0, 1, 1 }),
new Int32DataFrameColumn("R2", new[] { 1, 1, 2 }),
new StringDataFrameColumn("R3", new[] { "Z", "Y", "B" })
);
DataFrame merged = left.Merge(right, ["L1"], ["R1"], joinAlgorithm: JoinAlgorithm.Left);

Expected behavior
Expected to get this DataFrame instead of an ArgumentOutOfRangeException:
DataFrame expectedResult = new DataFrame(
new Int32DataFrameColumn("Index_left"),
new Int32DataFrameColumn("L1"),
new Int32DataFrameColumn("L2"),
new StringDataFrameColumn("L3"),
new Int32DataFrameColumn("Index_right"),
new Int32DataFrameColumn("R1"),
new Int32DataFrameColumn("R2"),
new StringDataFrameColumn("R3")
);

Screenshots, Code, Sample Projects
N/A

Additional context
I have code ready to fix this and will create a PR.