Fix updates in Cucumber tests with fixtures (fixes #483)

[elantsov]

Context

In Cucumber (Cucumber Spring in particular) when there is CucumberContextConfiguration class with Before/After fixtures it's impossible to attach links from steps and fixtures and in case of failed test the stacktraces are not getting attached as well.

In logs there appears something like:
ERROR io.qameta.allure.AllureLifecycle - Could not update test case: test case with uuid Example featuref213ed63-0e65-4e12-bf6a-ae5e40565d1cdummy step6 not found

The reason for this is that in AllureLifecycle methods startFixture and stopFixture contain thread context cleanup removing the information about the root (test case uuid).

Checklist

• Sign Allure CLA
• Provide unit tests

[elantsov]

Hey guys! Any chance this will be merged anytime soon? This is a significant issue for those using Allure with Cucumber.

[CLAassistant]

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