Fix: Computation of Total Number of Parameters

[mali-git]

What does this PR do?

This PR updates the computation of the total number parameters in a (sharded) model.
Previously, the parameter count only reflected the number of parameters in a single shard wher the model was sharded.

General Changes

• All ranks collectively reduce the total number of parameters.

Breaking Changes

• None

Checklist before submitting final PR

• My PR is minimal and addresses one issue in isolation
• I have merged the latest version of the target branch into this feature branch
• I have reviewed my own code w.r.t. correct implementation, missing type hints, proper documentation, etc.
• I have run a sample config for model training
• I have checked that all tests run through (python tests/tests.py)

[le1nux]

LGTM :)