Remove duplicative all-at-once concatenate with join operations

[d33bs]

Description

This PR removes a duplicative and all-at-once concatenate during CytoTable join operations. It was discovered while trying to replicate / confirm findings for #38 with SQ00014613.sqlite (which appears to no longer face direct challenges with data value translation but faces large memory resource consumption issues as a result of the removed block in this PR). After this is applied we should see performance benefits (as join concatenation will only take place once) and better opportunity to avoid memory resource constraint issues.

References #38
Likely effects discussion on recommendations in #163

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[kenibrewer]

Great find!

[d33bs]

Thanks @kenibrewer ! Merging this in.