add check for duplication during transcription in QC process

[eosnas]

in 2019 Heather Wilson (HMW) ACP data there appears to be duplication of transcribed data on Day = 11, transect = 33. In all data from 2007 to 2023 there are > 5000 duplicate observations that share exact time, location, species and all other data. Many of these are justified cases where the observer recorded multiple observation of the same species and observation type or number on the same WAV file. Another justified case might be when one observer copies the start or end locations from another observer. The occasion noted above had two start location recorded and then had many (~8) duplicate observations of various species such that a cut-and-paste error or that the same WAV file were transcribed multiple times.

There appear to be three occurrences of this in the data set from 2007 to 2023:
2007, RMD, transect 420 (maybe only 6 observations);
2015, HMW, transect 3; (about 34 observations)
2019, HMW, transect 33 (found above)

All of the above have two START points recorded at the same time. Maybe the best way to check for this is to produce a warning when multiple starts are present at the same position? Not sure if the above duplicate data should be deleted or left in?