ecl-ekf-tools: fix a bug related to time index calculation (#9489)
ecl-ekf-tools: fix a bug related to time index calculation (#9489)

- fix start and end time indices calculation
mje-nz/PX4-Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,acfloria/Firmware,PX4/Firmware,Aerotenna/Firmware,mcgill-robotics/Firmware,mcgill-robotics/Firmware,acfloria/Firmware,krbeverx/Firmware,krbeverx/Firmware,mje-nz/PX4-Firmware,mje-nz/PX4-Firmware,dagar/Firmware,dagar/Firmware,mcgill-robotics/Firmware,Aerotenna/Firmware,acfloria/Firmware,mcgill-robotics/Firmware,dagar/Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,krbeverx/Firmware,acfloria/Firmware,PX4/Firmware,dagar/Firmware,krbeverx/Firmware,Aerotenna/Firmware,mje-nz/PX4-Firmware,PX4/Firmware,dagar/Firmware,acfloria/Firmware,krbeverx/Firmware,Aerotenna/Firmware,PX4/Firmware,dagar/Firmware,dagar/Firmware,krbeverx/Firmware,PX4/Firmware,acfloria/Firmware,mcgill-robotics/Firmware,krbeverx/Firmware,PX4/Firmware,PX4/Firmware,mcgill-robotics/Firmware,acfloria/Firmware,Aerotenna/Firmware,mcgill-robotics/Firmware