[Bug] Allow for structured summary to account gracefully for steps without cv segment

[ardunn]

On the long novonix test file, cycle 4 is not shown in summary because the CV segment extraction prevents it from being added to the cycle. It should be shown as a cycle, but with the CV segment as nan.

[ardunn]

Note this even happens when the CV part is fixed, as incomplete cycles are excluded from the summary regardless because of this line:

if (
        (last_voltage.min() < cycle_complete_vmin)
        and (last_voltage.max() > cycle_complete_vmax)
        and (
        (summary.iloc[[-1]])["discharge_capacity"].iloc[0]
        > cycle_complete_discharge_ratio
        * (summary.iloc[[-1]])["charge_capacity"].iloc[0]
            )
):
    return summary
else:
    return summary.iloc[:-1]

This issue is tabled for now