GUID is a known function (#2590)

`GUID` is a known function.
`Guid` is an unknown function but PFx mistakenly finds it in the list of
unsupported known functions.


Before:

![image](https://github.com/user-attachments/assets/f29380d7-1f6d-48ab-9aa7-7af81a14c2e6)


After:

![image](https://github.com/user-attachments/assets/c218a9b4-16e8-4a33-a18e-87785e8115c7)

src/libraries/Microsoft.PowerFx.Core/Texl/BuiltinFunctionsCore.cs

@@ -18,7 +18,7 @@ namespace Microsoft.PowerFx.Core.Texl
         // instead of the classic "unknown or unsupported function".
         internal static readonly IReadOnlyCollection<string> OtherKnownFunctions = new HashSet<string>()
         {
-            "Assert", "Back", "Choices", "ClearData", "Concurrent", "Confirm", "Copy", "DataSourceInfo", "Defaults", "Disable", "Distinct", "Download", "EditForm", "Enable", "Errors", "Exit", "GUID",
+            "Assert", "Back", "Choices", "ClearData", "Concurrent", "Confirm", "Copy", "DataSourceInfo", "Defaults", "Disable", "Distinct", "Download", "EditForm", "Enable", "Errors", "Exit",
             "GroupBy", "HashTags", "IsMatch", "IsType", "JSON", "Launch", "LoadData", "Match", "MatchAll", "Navigate", "NewForm", "Notify", "PDF", "Param", "Pending", "Print", "ReadNFC",
             "RecordInfo", "Relate", "RemoveAll", "RemoveIf", "RequestHide", "Reset", "ResetForm", "Revert", "SaveData", "ScanBarcode", "Select", "SetFocus",
             "SetProperty", "ShowColumns", "State", "SubmitForm", "TraceValue", "Ungroup", "Unrelate", "Update", "UpdateContext", "UpdateIf", "User", "Validate", "ValidateRecord", "ViewForm",