_add_config_options() can ignore some checkboxes

[alkanen]

The _add_config_options() function in the demo truncates options at the end if the number of names isn't evenly divisible by number of columns:

https://github.com/hoffstadt/DearPyGui/blob/3ce32db5bdaa7c1b9f202ffdf7fe0e2505b7810f/dearpygui/demo.py#L38

An example can be found in the "Color Picker & Edit" -> "Color Picker" checkbox area where there are ten items divided into three columns and the "alpha_bar" checkbox isn't showing.

Another example is in "Plots" -> "Subplots" with five names over two columns and "link_all_y" missing from the grid of checkboxes.

[alkanen]

I'm not sure about the code policies for this project, but this change to the loop at the end of the function makes it work:

        for i in range(int(ceil(len(names) / columns))):

            with dpg.table_row():
                for j in range(columns):
                    index = i * columns + j
                    if index >= len(names):
                        break

                    dpg.add_checkbox(
                        label=names[index],
                        callback=_config,
                        user_data=item,
                        default_value=dpg.get_item_configuration(item)[names[index]],
                    )

[alkanen]

I guess a try/except IndexError block might be more pythonic