Integrated Alerting: Add/Update Alert Rule: Unknown parameters [threshold].

User Impact:
Unknown parameters [threshold] while creating/editing Alert Rule for template without Threshold.

Workaround:
Not to specify Threshold while creating a rule.

Steps to reproduce:
Navigate to Settings and enable IA.
Navigate to IA >>>Alert Rules>>>Create Rule
Add Threshold value and information needed to create a rule

or Update the existing Alert Rule (without threshold specified).

Actual result:
The rule can not be created in fuser specifies Threshold for Template without Threshold.
Expected result:
Disable Threshold field if Template without Threshold parameter was chosen.