Add set_root_weights()

[JohnReedV]

Description

This PR implements a new function set_root_weights() for setting root weights with the coldkey.

Changes

• Created set_root_weights which contains the original logic associated with the root network from set_weights.
• set_weights now rejects calls for the root network.
• Root specific operations in set_weights have been removed.
• Added & updated associated unit tests.

Related Issue(s)

N/A

Type of Change

• 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)
• Documentation update
• Other (please describe):

Breaking Change

Calls to set_weights for the root network will now be rejected. Instead they should call set_root_weights.

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have run cargo fmt and cargo clippy to ensure my code is formatted and linted correctly
• 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 unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshots (if applicable)

Please include any relevant screenshots or GIFs that demonstrate the changes made.

Additional Notes

Please provide any additional information or context that may be helpful for reviewers.

[sam0x17]

I know we haven't really started doing this yet but ideally these should be doc comments

[distributedstatemachine]

TODO:

• This release has to be coordinated with @opentensor/cortex cc @sam0x17