CPack/DEB: Remove extra newline at the end of .deb control file

It effectively created a control file with two stanzas when package file
data is appended, one of which lacks required parameters, making this
package impossible to use in a package repository.

Fixes: #26975

Source/CPack/cmCPackDebGenerator.cxx

@@ -176,7 +176,7 @@ void DebGenerator::generateControlFile() const
       totalSize += cmSystemTools::FileLength(file);
     }
   }
-  out << "Installed-Size: " << (totalSize + 1023) / 1024 << "\n\n";
+  out << "Installed-Size: " << (totalSize + 1023) / 1024 << "\n";
 }
 
 bool DebGenerator::generateDataTar() const