add input_info to nncf config when not defined by user

[djdameln]

Description

• Adds input_info to the NNCF config when this has not been defined by the user in the config.yaml.

This allows users to enable NNCF by adding the following to config.yaml:

optimization:
    nncf:
        apply: true

Where previously, the following was needed:

optimization:
    nncf:
        apply: true
        input_info:
            sample_size: null

Changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist

• My code follows the pre-commit style and check guidelines of this project.
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing tests pass locally with my changes

[samet-akcay]

Do you think if we should add the nncf settings to the config files as well? Currently, none of the config files have nncf