Plugin setting to choose Kotlin generation doesn't work

[Damtev]

Description

Running plugin, we have settings for UnitTestBot. One of them is Generated test language - Java by default, with an experimental Kotlin option. But this option does not work, and it is impossible to generate a test in Kotlin language.

To Reproduce

1. Use runIde task and open any Java project
2. Set Generated test language to Kotlin (experimental)
3. Run test generation action with any options for any method

Expected behavior

Kotlin test file is supposed to be generated (maybe uncompiled, but existed).

Actual behavior

Java test file is generated, and Generated test language is reset to Java.