Useful for dealing with meets where some events are split by 50 and others by 25.
correct_split_distance_helper(df_helper, new_split_length_helper)
a data frame where all values have been pushed left, replacing `NA`s, and all columns containing only `NA`s have been removed
a data frame having some split columns (Split_50, Split_100 etc.)
split length to rename split columns based on
correct_split_distance_helper
is a helper function inside
correct_split_distance