[Request impl] Gracefully error out in ETDump

[Gasoonjia]

Context and Target:

In the etdump_flatcc.cpp file, there are instances where the class may directly raise an error and shut down the system when encountering issues. An example can be found here.
The preferred approach is to handle these errors gracefully by returning an error code to the user, allowing them to decide how to address the issue.

TODO:

• Modify the code to return an error code to the user instead of crashing the system when an error occurs.
  If applicable, use the ET_CHECK_OR_RETURN_ERROR macro, as seen here.
  Alternatively, manually return an error code, as demonstrated here, if there's extra work like free need to be done.

• Update the return type of the function as necessary and ensure corresponding tests are updated.

Consider breaking this task into two or three pull requests for better structure and clarity.

[zhongmingyuan]

I want to work on it as a learning opportunity. May I take this issue?