fix: Conditional params safeguard (HEXA-1687)

[mrivar]

Fixing bug in https://github.com/BLSQ/snt_development/actions/runs/27815160427/job/82314423275

❌ Error while importing pipeline: "[{'message': "Variable '$input' got invalid value 
{'code': 'dhis2_connection', 'type': 'dhis2', 'name': 'DHIS2 connection', 'choices': None, 
'help': 'DHIS2 connection ID', ..., 'multiple': False, 'directory': None, 'disables': None, 
'disableWhen': True} at 'input.parameters[0]'; Field 'disables' is not defined by type 
'ParameterInput'.", 'locations': [{'line': 2, 'column': 37}]}, {'message': "Variable '$input' 
got invalid value {'code': 'dhis2_connection', 'type': 'dhis2', 'name': 'DHIS2 connection', 
'choices': None, 'help': 'DHIS2 connection ID', ..., 'multiple': False, 'directory': None, 
'disables': None, 'disableWhen': True} at 'input.parameters[0]'; Field 'disableWhen' is 
not defined by type 'ParameterInput'."

Changes

The root cause was a payload field the server's ParameterInput doesn't define.

• This safeguard will add only the new values (disables and disableWhen) when they actually exist, thus avoiding having issues with unupdated openhexa instances.
• Added tests to ensure this doesn't happen in the future