Remove string concatentations from long worksheet formulas that are exported by Google Sheets.

EPPlus/ExcelWorksheet.cs

diff --git a/EPPlus/ExcelWorksheet.cs b/EPPlus/ExcelWorksheet.cs
index ea64e83..982c081 100644
--- a/EPPlus/ExcelWorksheet.cs
+++ b/EPPlus/ExcelWorksheet.cs
@@ -122,6 +122,7 @@
 
             public static string RemoveDummyFunction(string formula)
             {
+                const string DummyFunctionConcatenate = "\"&\"";
                 const string DummyFunctionPrefix = "IFERROR(__xludf.DUMMYFUNCTION(\"";
                 const string DummyFunctionSuffix = "\"),\"";
 
@@ -143,6 +144,13 @@
                 // Trim Prefix
                 formula = formula.Replace(DummyFunctionPrefix, "");
 
+                // Remove string concatentations from long formulas.
+                // Google break the quoted string into 254 character segments which are concatenated.
+                if (formula.Length >= 254)
+                {
+                    formula = formula.Replace(DummyFunctionConcatenate, "");
+                }
+
                 // Replace doubled quotes with single quote
                 formula = formula.Replace("\"\"", "\"");