fix(mssql): upsert query with falsey values

[patrickcarnahan]

Pull Request check-list

Please make sure to review and check all of these items:

• Does npm run test or npm run test-DIALECT pass with this change (including linting)?
• Does the description below contain a link to an existing issue (Closes #[issue]) or a description of the issue you are solving?
• Have you added new tests to prevent regressions?
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Description of change

properly determines if a value used in a filter clause for upsert is relevant. currently there is a bug where it treats "falsey" values as not being specified, making it impossible to use something like a default value of 0 in a unique key and then filter by that value.

closes #11902
closes #11684

[codecov]

Codecov Report

Merging #12453 into master will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #12453      +/-   ##
==========================================
+ Coverage   96.44%   96.46%   +0.02%     
==========================================
  Files          95       95              
  Lines        9192     9192              
==========================================
+ Hits         8865     8867       +2     
+ Misses        327      325       -2     

Impacted Files	Coverage Δ
src/dialects/mssql/query-generator.js	95.69% <100.00%> (ø)
src/dialects/postgres/connection-manager.js	95.80% <0.00%> (+1.39%)	⬆️

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[patrickcarnahan]

appears that the postgres tests failed even though they should not be impacted by these changes.

[sushantdhiman]

You can open this PR for v6 branch if you want this released to npm

[patrickcarnahan]

@sushantdhiman thanks! The project that needs this fix is currently on v5. Would it be accepted there as well or is v6 the preferred target? I can open both if that works.

[sushantdhiman]

@patrickcarnahan I would like to avoid pushing too many releases for v5 but bug fixes are allowed. I have merged PR for v6, please open a PR for v5 if your project needs it.

[srikanth2042]

@patrickcarnahan @sushantdhiman this bug exists in v4 as well, can we expect a bug fix in v4 as well?

[sushantdhiman]

@srikanth2042 No, v4 has been deprecated and not safe to use in production