Description of problem:

There are too many dialogs, so i tried to backup all and then start deleting the older or unused ones.
But i was unable to export all service dialogs at the same time.

When performing an export of all service dialogs (there are a lot of long dialogs) one
gets an 502 error and it is not possible to export the dialogs.

Version-Release number of selected component (if applicable):
5.8.x (also encountered on 5.9.x)

How reproducible:
always

Steps to Reproduce:
1. Go to Automation -> Automate -> Customization -> Select Import Export
2. Select all existing dialogs (almost 100 dialogs)
3. Press the button "Export"
4. After some time, the error 502 appears.
5. Individual or sometimes a group of dialogs can be exported

Actual results:
unable to export all dialogs

Expected results:
being able to export all existing dialogs

Additional info:
On the logs one can see that the dynamic methods are being executed.
This lasted a lot of time, due to the quantity and complexity (several dynamic methods) of the dialog.
I found very strange that the methods are being executed when just exporting the dialog as a yaml.