fix: substituted a UT_ASSERT with an assert from GTEST

[EuphoricThinking]

Description

The PR is a part of a major fix: to substitute UT_ASSERTs with asserts provided by GTEST, in multiple files.

Ref. #569

Checklist

• [ ] Code compiles without errors locally
• [ ] All tests pass locally
• [ ] CI workflows execute properly

• [ ] CI workflows, not executed per PR (e.g. Nightly), execute properly
• [ ] New tests added, especially if they will fail without my changes
• [ ] Added/extended example(s) to cover this functionality
• [ ] Extended the README/documentation
• [ ] All newly added source files have a license
• [ ] All newly added source files are referenced in CMake files
• [ ] Logger (with debug/info/... messages) is used