d09193b08a introduced a regression in
StringExtensions.FindLast. StringExtensions.GetFile was also affected as it
relies on FindLast. This in turn broke the project exporter as it uses GetFile.
The cause of the regression is that now FindLast is calling LastIndexOf
with 'startIndex: 0'. This should be 'startIndex: str.Length - 1' instead.
Also fixed another regression in the project exporter:
de7c2ad21b moved 'GodotTools/GodotSharpExport.cs'
to 'GodotTools/Export/ExportPlugin.cs' and in doing so accidently reverted
the changes from commit e439581198.
20d7013c60