Refactor Stream gRPC handlers to remove exception handling (#34)

Changed: Simplified the BatchAppend method by removing the try-catch
blocks for IOException, TaskCanceledException,
InvalidOperationException, and OperationCanceledException, as they were
previously ignored. This streamlines the code and improves readability.

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis