Added fix for custom iconsets (#2042)

* Added fix for custom iconsets

* Update WorksheetXmlWriter.cs

Removed commented code

---------

Co-authored-by: Mats Alm <897655+swmal@users.noreply.github.com>

Author: OssianEPPlus

src/EPPlus/ConditionalFormatting/Contracts/IExcelConditionalFormattingFourIconSet.cs

@@ -24,7 +24,7 @@ public interface IExcelConditionalFormattingFourIconSet<T> : IExcelConditionalFo
   {
     #region Public Properties
     /// <summary>
-    /// Icon4 (part of the 4 ou 5 Icon Set)
+    /// Icon4 (part of the 4 or 5 Icon Set)
     /// </summary>
       ExcelConditionalFormattingIconDataBarValue Icon4 { get; }      
     #endregion Public Properties

src/EPPlus/Core/Worksheet/XmlWriter/WorksheetXmlWriter.cs

@@ -1347,10 +1347,7 @@ private string GetXMLCFExt(string prefix, ExcelConditionalFormattingRule format,
                 cache.Append($"<{prefix}cfRule type=\"iconSet\" priority=\"{format.Priority}\" id=\"{{{uid}}}\">");
                 cache.Append($"<{prefix}iconSet ");
 
-                if (isCustom == false)
-                {
-                    cache.Append($"iconSet=\"{iconSetString}\"");
-                }
+                 cache.Append($"iconSet=\"{iconSetString}\"");
 
                 if (showValue == false)
                 {

src/EPPlusTest/ConditionalFormatting/CF_IconSetTests.cs

@@ -611,5 +611,18 @@ public void CF_IconSetReadIDGenerated()
                 SaveAndCleanup(p);
             }
         }
+        [TestMethod]
+        public void CF_IconSetReadCUSTOMEXCEL()
+        {
+            string id = "";
+            using (var p = OpenTemplatePackage("IconTest_CF.xlsx"))
+            {
+                var ws = p.Workbook.Worksheets[0];
+                ws.Cells["B1"].Value = 5;
+
+                SaveAndCleanup(p);
+            }
+        }
+
     }
 }