WASM: Simplifies PVM handling of errors

Context

Currently, the PVM uses two functions to handle the exceptions:

• one to know whether it is a known exception from the interpreter
• another to extract the encodable information from the exception

This MR simply merges the two to avoid maintaining the two same list of exceptions.

Manually testing the MR

Run the CI

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR