annotation @Severity doesnt work in Junit-allure

Annotation _@Severity_ doesnt work in Junit-allure, from version **allure-junit4 "2.10.0"** to current.

In test like this,

```
@Epic( "1")
@Feature("2")
@Story("3")
@Owner("4")
@Test
@Severity(SeverityLevel.CRITICAL)
public void testseverity() {
registrationPage.emailNotUniqueReg();

}
}

```
after execution **mvn clean test** и **mvn allure:serve**

severity annotations doesnt work (on reporting page it shows like "_Normal_"). The json autogenerated results file also doesnt have this annotation. The rest annotations work.

In version allure-junit4 "2.9.0" and below there is no such problem

Start with the provided JUnit 4 test using @Severity(SeverityLevel.CRITICAL), then compare allure-junit4 2.9.0 with 2.10.0 and current versions. Run mvn clean test and mvn allure:serve, and inspect the generated results JSON. Done means the report shows CRITICAL and the JSON contains the severity annotation.

Written by the indexing model from the issue text.