No percent shown when 'Test generation method' is set to 'Symbolic executuion'

[tyuldashev]

Description

In UTBot settings percent not shown when user set it to 'Symbolic execution only'

To Reproduce

Steps to reproduce the behavior:

Example:

1. Open UTBot setting: Settings->UnitTestBot
2. Move slider 'Test generation method' to the right to make it 100% Symbolic execution
3. OK to save and close settings
4. Reopen settings again

Expected behavior

In the settings percent shown: 'Fuzzing' = 0%, 'Symbolic execution' = 100%

Actual behavior

No percent shown

Visual proofs (screenshots, logs, images)