get_slice_memory_size undercounts offsets buffer for Utf8/Binary arrays

[Rich-T-kid]

Is your feature request related to a problem or challenge?

get_slice_memory_size undercounts the offsets buffer for Utf8/Binary (and LargeUtf8/LargeBinary) arrays.

Describe the solution you'd like

update get_slice_memory_size to be more accurate for string arrays/binary arrays

Describe alternatives you've considered

n/a

Additional context

#10383 (comment)

[Rich-T-kid]

take

[Rich-T-kid]

see #10383 (comment)

[Rich-T-kid]

may have closed this a bit early. #10406 fixes an off by one error but this isn't the main issue that I found in #10383