Add an understandable description of errors in the Rest API

[NikitaShchienko]

Environment

Jmix version: 2.1.1

Bug Description

Make an understandable error message and correct the status

Steps To Reproduce

1 - Create a Jmix project with a Reports add-on
2 - Create a report with required parameters
3 - Run the report by Rest API

Current Behavior

Response: Status - 500

{
    "timestamp": "2023-12-12T16:03:08.369+00:00",
    "status": 500,
    "error": "Internal Server Error",
    "path": "/rest/reports/run/a2f873d6-45f0-1c09-73c1-0696c535cc63"
}

Exception:

Request processing failed: java.lang.IllegalArgumentException: Required report parameter "entity" not found
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1019) ~[spring-webmvc-6.0.12.jar:6.0.12]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:914) ~[spring-webmvc-6.0.12.jar:6.0.12]

Expected Behavior

Response: Status - 400

{
    "error": "Run report error",
    "details": "Required 'entity' param is missing"
}

[konyashkina]

Tested on
Jmix version: 2.1.999-SNAPSHOT
Jmix Studio plugin version: 2.1.3-233
IntelliJ version: IntelliJ IDEA 2023.3.3