Close streams after they are used

[prd-fox]

Follow-up of #719
Part of #705

Close input streams after they are used so we don't hit descriptor limits.
This only matters when using the directory store mode for loading data. We close each stream after it is used so that we don't have a bunch of dangling file descriptors and hit the limit.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@9ada92c). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master     #721   +/-   ##
=========================================
  Coverage          ?   99.44%           
  Complexity        ?     1890           
=========================================
  Files             ?      285           
  Lines             ?     5621           
  Branches          ?      284           
=========================================
  Hits              ?     5590           
  Misses            ?        5           
  Partials          ?       26

Impacted Files	Coverage Δ	Complexity Δ
...uorum/tessera/data/migration/JdbcDataExporter.java	100% <100%> (ø)	4 <0> (?)
...rum/tessera/data/migration/SqliteDataExporter.java	100% <100%> (ø)	6 <0> (?)

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