UI. IDEA plugin dialog. Hide UI possibility to change destination package #488

Description

Hide "Specify destination package" and "Destination package" fields from UI.

To Reproduce

Preconditions:

1. IntelliJ IDEA is running.
2. New version of UTBotJava plugin is installed.
3. Project with JDK 8-11 is opened.

Steps to reproduce the behavior:

1. Create a package in sources root, add a class to it
2. Open dialog to Create tests with UTBot... for the class

Expected behavior

Need to hide Specify destination package checkbox and Destination package editable dropdown from UI.
The use-cases for them are not obvious. What to do with package-private classes/members? What to do with relative imports?

Suggested solution: hide these two fields from UI. User can manually move generated tests to the needed destination and resolve the conflicts.

Actual behavior

There is Specify destination package checkbox and Destination package editable dropdown.

Visual proofs (screenshots, logs, images)

Environment

Windows 10 Pro
IntelliJ IDEA 2022.1.3
JDK 8 / 11 , Gradle project