fix(query-interface): allow passing null for query interface insert

[SimonSchick]

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Description of change

Add null as allowed parameter to insert on queryInterface and adjust return type of bulkInsert to include number as it can be one.

[codecov]

Codecov Report

Merging #11931 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #11931   +/-   ##
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  Coverage   96.23%   96.23%           
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  Files          95       95           
  Lines        9196     9196           
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  Hits         8850     8850           
  Misses        346      346

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[papb]

When does it return an object and when does it return a number? And by the way what is this object/number? I couldn't find in the docs 😅

[SimonSchick]

The auto increment index when using mysql.
Apparently this only returns an object under postgres?