Normalize `IndexSet.data` DB storage #467

Job	Run time
Code quality	59s
py3.10 \| backend=sqlite,rest-sqlite,postgres,rest-postgres \| with-pyarrow=false \| pgsql=16 \| pandas=false	13m 31s
py3.11 \| backend=sqlite,rest-sqlite,postgres,rest-postgres \| with-pyarrow=false \| pgsql=16 \| pandas=false	12m 46s
py3.12 \| backend=sqlite,rest-sqlite,postgres,rest-postgres \| with-pyarrow=false \| pgsql=16 \| pandas=false	14m 53s
py3.12 \| backend=sqlite,rest-sqlite \| with-pyarrow=true \| pgsql=16 \| pandas=false	5m 4s
py3.12 \| backend=postgres,rest-postgres \| with-pyarrow=false \| pgsql=15 \| pandas=false	9m 40s
py3.11 \| backend=sqlite,rest-sqlite \| with-pyarrow=true \| pgsql=16 \| pandas=2.1.3	3m 57s
py3.10 \| backend=sqlite,rest-sqlite \| with-pyarrow=true \| pgsql=16 \| pandas=2.1.0	4m 14s
	1h 5m 4s

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