Fix: Correctly compute Java agent list loggers response size

Fix: Correctly compute Java agent list loggers response size

The code was assuming that (number of characters == number of bytes),
which is not always the case!

The notions of number of bytes and data sizes only make sense when
the strings are encoded into byte arrays. The response's getBytes()
method should the only one handling these concepts.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>