Steps to reproduce:

• Open Data collection => Templates
• Open template "Linux by Zabbix agent" (or "Linux by Zabbix agent active")
• Press "Clone", enter template name, press "Add"

Result:
Template is not cloned:

Cannot add template
Invalid parameter "/15/preprocessing/2/params": value must be empty.

Item prototypes "Interface {#IFNAME}: Bits received" and "Interface {#IFNAME}: Bits sent" have parameter "8" in preprocessing step 2 "Change per second":

 
Linux by Zabbix agent:          66359 |2 |10 |8   66362 |2 |10 |8
 Linux by Zabbix agent active:   66412 |2 |10 |8   66415 |2 |10 |8

Expected: "Change per second" steps have no parameters (as in template YAML files), templates can be cloned.

Affected selenium test: testFormTemplate::testFormTemplate_CloneTemplate