Fix ParseJsonHelper not storing parsed result in variable (if any) when json is empty

[G-Basak]

Parse-Json-Helper for Handlebars should store the parsed json in variable specified and should evaluate to empty string for that section.

For example :

{{#parseJson 'parsedObj'}}
{"key":"value"}
{{/parseJson}}

{{#assign 'json'}}
{"key":"value"}
{{/assign}}
{{parseJson json 'parsedObj'}}

In both scenario, it will parse and store the json {"key":"value"} to a variable named parsedObj, and evaluate to an empty string for that section.

However, this was not happening when that inner-json was empty like below. Nothing was being stored in the variable, and the section was being evaluated to {}

{{#parseJson 'parsedObj'}}
{}
{{/parseJson}}

{{#assign 'json'}}
{}
{{/assign}}
{{parseJson json 'parsedObj'}}

References

closes #2085

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[oleg-nenashev]

Thanks for the patch!