Clarify consolidate command help text

[evgeny-stakewise]

Rewrites the consolidate command help text to accurately describe its behavior:

• The command consolidates validators into 0x02 (compounding) validators.
• When no public keys are provided, it automatically picks eligible 0x01 validators and consolidates them (a 0x01 validator with no separate target is switched to 0x02).
• To consolidate 0x02 validators, or to choose specific validators, explicit --source-public-keys and --target-public-key options must be passed (auto-pick is not implemented for 0x02).