Improve error popup for test failures- go to assertion and don't duplicate test code

[chrmarti]

Testing #24505

I clicked on a test failure in the test explorer and it navigated to the test function telling me about the failed test assertion. It should instead directly go to the failed assertion. When directly going to the failed assertion there is no need for duplicating the test's code in the zone widget (without syntax highlighting).

[eleanorjboyd]

Agree with this as there are feature improvements possible in the error pop-up. Right now we take the information output by pytest for the specific test and return it directly in this section. Would be great if there was more sophistication to not duplicate information etc