"Test generation method" setting UI update

[olganaumenko]

Description

As the part of Settings UI revision #753, please change the UI for "Simpler — Deeper" setting.

Steps To Reproduce

IntelliJ IDEA → File → Settings... → Tools → UtBot

See the screenshot attached:

Actual (OLD) and expected (NEW) behavior

(OLD) Code analysis:
Simpler — Deeper

(NEW)

a) Please rename
Test generation method:
Fuzzing — Symbolic execution

b) Please add dynamic percentage under labels.

TODO:
Please add the tooltip for the setting:
While fuzzer "guesses" the values to enter as much execution paths as possible, symbolic executor tries to "deduce" them. Choose the proportion of generation time allocated for each of these methods within Test generation timeout.