NoClassDefFoundError for optional dependency on JsonProviderFactory

[oswaldobapvicjr]

Describe the bug
JsonProviderFactory throws a NoClassDefFoundError for an optional (not required) JsonProvider not in the classpath during class loading.

To Reproduce
Steps to reproduce the behavior:

1. Import jsonmerge with no optional dependency.
2. Create a new JsonMerger without specifying a concrete Provider (declare a JSON object type instead):

JsonMerger<JsonObject> merger = new JsonMerger<>(JsonObject.class);

Expected behavior
A new JsonMerger with the JsonSmartJsonProvider attached should be created and delivered.

Screenshots
N/A

Additional context
N/A