[variable mediator] Issue in variable type casting

[GDLMadushanka]

Description

When we specify the data-type of the variable mediator to INTEGER and give an expression. which results in a double value, variable mediator cast the type of value to integer which is expected.
But, even for a value like 8.99 its giving 8 as output.
We need to decide a proper type casting method and stick to it. Even converting 8.99 -> 8 is OK if we officially state that in docs.
If we are sticking to the existing behaviour, consider this as a doc issue and add it to the docs.

Steps to Reproduce

<variable name="book2price" type="INTEGER" expression="${payload.store.book[1].price}"/>
<log category="WARN">
     <message>${vars.book2price}</message>
</log>

Version

4.4.0

Environment Details (with versions)

No response