Cpp KVS does not reflect if the default value is set.

[Saumya-R]

In the rust code, "kvs.is_value_default()" function, can detect if get value is a default or set value. E.g. for the scenario where for key x there is a default 10 and then it is explicitly set to 10, kvs.is_value_default() will return false as explicitly used value is used.

However, there is no matching function on the cpp side. The closest function is kvs.has_default_value that will return true for the above scenario.

Expectation is that kvs.has_default_value in CPP works like rust's kvs.is_value_default(), i.e, the behaviour of rust and cpp code are same.

[Saumya-R]

The has_default_value() in CPP is expected to behave same as is_value_default() function in RUST where this functions returns the information if the default value is explicitly updated or changed or updated . This function is not updating the value as expected.