Spreadsheet Charts don't honor the "no fill" attribute

[WoozyG]

when determining line and fill colors from an <spPr> or element in an OOXML (XLSX) spreadsheet, there are special attributes possible for these: <noFill/>. If present, the color is effectively transparent.

This can be handled by augmenting color conversion routines for these element types to use a color configuration with 0.0 for opacity (full transparency) such as

new ColorProperties(new int[] {0, 0, 0}, 0d)

or

new SolidColor(0, 0, 0, 0d)

This file Hospital VBP Penalty Tool NEW.xlsx shows the issue. The series named "Axis" in each chart should have transparent (no) fill and line colors.