[Test Improvement] Check return type of RefreshPageElementsHelper update methods

Problem/Motivation

Currently the test does not checks the return type of RefreshPageElementsHelper methods. This check is necessary for better input/output testing of RefreshPageElementsHelper methods.

Proposed resolution

Basically it will check whether the returned value from update methods is an instance of RefreshPageElementsHelper class. It is recommended to create a custom assertion that would check this.

Remaining tasks

Add the custom assertion in all the test methods.

User interface changes

N/A

API changes

N/A

Data model changes

N/A