Introduce SameSubnetId error for move and swap stake extrinsics.

[shamil-gadelshin]

Description

This PR introduces SameSubnetId error for all extrinsics related to moving stake (move, stake, and their versions with limits). The change was introduced in the shared inner method validate_stake_transition. The new code prevents the stake from moving for the same origin and destination subnets for the same coldkey and hotkey. The PR also changes tests and related benchmarks.

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

The PR introduces a new error for the same subnets, coldkeys, and hotkeys.

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