Update color logic in getColour function

The color logic within the `getColour` function in Constants.tsx has been modified. The color for the 'yes' diagnostic is updated from "text-red-400" to "text-red-600" in order to provide more optic distinction in the application's UI.

webapp/src/data/Constants.tsx

@@ -141,7 +141,7 @@ export const DatabaseColumns = [
 
 
 function getColour(diagnostic) {
-    return diagnostic !== "yes" ? "text-red-400" : (diagnostic === "check" ? "text-yellow-600" : "")
+    return diagnostic !== "yes" ? "text-red-600" : (diagnostic === "check" ? "text-yellow-600" : "")
 }