Code Review Bench PR #14646 - Replace fragile dict stored-key API with getKeyId callback

[tomerqodo]

Code Review Bench PR redis#14646

Original PR Title: Replace fragile dict stored-key API with getKeyId callback
Original PR Description: ## Summary

• Simplifies the dictionary API for handling stored keys by replacing the complex stored-key mechanism with a cleaner getKeyId callback approach.
• As part of this effort, following Hash - Unify Field-Value into a single struct along with dict no_value=1 redis/redis#14595, hash field-value pairs were unified into a single Entry structure
  with the sds field at the start. Since both stored keys (Entry*) and lookup keys
  (sds) can now be trivially compared as sds strings, first two commits starts with cleanups of dictUseStoredKeyApi() for hash data type.

dict API Changes

• Removed: storedHashFunction, storedKeyCompare callbacks and dictUseStoredKeyApi() flag
• Added: Single dictType.keyFromStoredKey callback that extracts the key identifier from stored objects
• Simplified: All dict operations now automatically extract keyId when needed, eliminating manual flag toggling
• Clarified API: Dict function declarations now marks where they expects stored-key and when lookup key.

No performance impact.

Original PR URL: redis#14646