fix(server/db-streaming): attempt to reduce remaining leaky connections

[iainsproat]

Description & motivation

We still have some leaky connections. This is a guess as to what the cause may be.

In this PR we are re-introducing the workaround that knex originally suggested. Although it wasn't necessary to resolve the test that recreated the issue, there is perhaps another root cause (the request closing) that was not recreated by the test.

Mostly a guess, and will observe the impact of this change on actual data once applied.

Changes:

To-do before merge:

Screenshots:

Validation of changes:

Checklist:

• My pull request follows the guidelines in the Contributing guide?
• My pull request does not duplicate any other open Pull Requests for the same update/change?
• My commits are related to the pull request and do not amend unrelated code or documentation.
• My code follows a similar style to existing code.
• I have added appropriate tests.
• I have updated or added relevant documentation.

References

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[iainsproat]

Closed until results of merging #3938 can be observed.