3570849 - Issue with `fillProperty` in Gantt Chart Container from `sap.gantt.simple` Library

When using the Gantt Chart Container from the `sap.gantt.simple` library in SAPUI5 version 1.120.25, the `fillProperty` for shapes does not accept standard CSS color names. Specifically, using the color name "sky blue" for a `BaseRectangle` results in the Gantt Chart failing to load, as it detects the color name as a string instead of a valid color.

- SAPUI5 version: 1.120.25
- Library: `sap.gantt.simple

Gantt Chart, `sap.gantt.simple`, `fillProperty`, CSS color names, hexadecimal color, RGB color, SAPUI5, version 1.120.25, BaseRectangle, rendering issue. , KBA , CA-UI5-CTR-GNT , Gantt Chart Control , Problem