[ANCHOR-346] Fix trailing comma in assets JSON file causes a "null" assets

[lijamie98]

Description

• Fix trailing comma in assets JSON file causes a "null" assets

Although the trailing comma in JSON does not cause gson parsing failure, it creates a null entry in the result Assets object. The PR removes the null entry.

Context

• Bug fixe.

Testing

• ./gradlew test

Documentation

N/A

Known limitations

N/A