Use electron scpot estimation rather than EFI for probes A and D

[jameswilburlewis]

From Vassilis:

I see this has been implemented for TH-A and TH-D, meaning we are not getting useful information from the EFI scpot from these spacecraft any longer. In fact, because the EFI has been not fully calibrated the EFI scpot seems out of order on these spacecraft for a long time. Can you please implement the same treatment for scpot plot on electron spectra for these 2 spacecraft as for TH-E?

For TH-A since Jan. 1st 2025.
For TH-D since Oct 26th, 2024.