Add missing search using POST HTTP method to OpenAPI specification

[delopst]

In OpenAPI specification searching using the POST HTTP method is missing.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 83.54%. Comparing base (406db33) to head (66b3475). Report is 55 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #6354 +/- ## ============================================ - Coverage 83.54% 83.54% -0.01% - Complexity 27432 27629 +197 ============================================ Files 1707 1720 +13 Lines 106185 106964 +779 Branches 13397 13455 +58 ============================================ + Hits 88710 89358 +648 - Misses 11750 11828 +78 - Partials 5725 5778 +53 ```

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