Changing the qualification level leads to an error message

[KonzeptAcht]

Describe the bug
When changing some of the qualification levels, an error message is displayed. The minimum value returned in the popup is always the currently specified value.

To Reproduce
Steps to reproduce the behavior:

1. Go to MyPrintEN
2. Go to Asset: Server management -> threat label: Equipment malfunction or failure -> Vulnerability label: No service level management
3. Change the qualification level from 5 to 1
4. See error

Expected behavior
A change of the qualification level without error message

Screenshots

Desktop (please complete the following information):

Questions	Answers
Type of issue	Bug
OS version (server)	Ubuntu 18.04 LTS
OS version (client)	MacOS, Win10
PHP version	7.4
MONARC version / git hash	2.9.16
Browser	Firefox, Chrome, Safari

Additional context
The error message appears in both our and the my.monarc instances

[ruslanbaidan]

The first thing is to understand that reduction of vulnerability qualification level on treated risks (which have Reduction treatment) means that the situation changed and some controls implemented. Normally it is not suppose to be done this way and performed by recommendations implementation.

The reason of the error message is because you are trying to change vulnerability rate from 5 to 1 (changing to 2 is not possible as well), which means reducing of Vulnerability level by 5 - 1 = 4 points, which is not possible as the level is 2:

It is possible to change the vulnerability level to 3, which means the Vulnerability level will be reduced by 5 - 3 = 2 points and the value will be 0: