[BUG] When setting the 'wrong' Result output of an HTTP endpoint activity - it can crash the API/POD

## Description
When setting the 'wrong' Result output of an HTTP endpoint activity - it can crash the API/POD

## Steps to Reproduce
1) Create a simple workflow : like so (attached)
2) create some variables:
3) Set the Result to any of variables 1-2-4
4) run the workflow - it will succeed / as it will return a 200
5) but the instance will not be listed, when saving will try to convert something which it cant / resulting in a restart of the pod.
The only way that it will work is when u use the variable HTTPR: storage = memory

3. **Attachments**:
[workflow-9.txt](https://github.com/user-attachments/files/17326843/workflow-9.txt)

4. **Reproduction Rate**: Every time.

## Expected Behavior
Ui validation to exclude these options.

## Actual Behavior
Application crash.

## Environment
Client version: 3.2.0-rc5.500
Server version: 3.2.0-rc5.2074