private void checkName(String name) throws DuplicateNameException {
		DataType dt = originalDTM.getDataType(getOriginalCategoryPath(), name);
		if (dt != null && originalDTM.getID(dt) != originalCompositeId) {
			throw new DuplicateNameException("Data type named " + name + " already exists");
		}
	}
Validates that the data type indicated by the string can be set as the data type
at the indicated row index. If the named data type can be various sizes, this
method will prompt the user.
@param rowIndex the row index
@param dtString the string representing the data type.
@return a valid data type instance or null if at blank line with no data type name.
@throws UsrException indicating that the data type is not valid.
Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/compositeeditor/CompositeEditorModel.java