fix: address review round 3 for migrate-core (#560)

- Fix has_operations treating empty string prefix as falsy (use 'is not None')
- Normalize single-element list prefix to string in _extract_rename_operations
- Close Redis client created in _check_svs_vamana_requirements
- Handle renamed vector fields in estimate_disk_space
- Fix percent_indexed=None when indexing flag is present
- Remove accidentally committed docs/dev/pr-review-triage.md

Author: nkanu17

redisvl/migration/models.py

@@ -78,7 +78,9 @@ class RenameOperations(BaseModel):
     @property
     def has_operations(self) -> bool:
         return bool(
-            self.rename_index or self.change_prefix is not None or self.rename_fields
+            self.rename_index
+            or self.change_prefix is not None
+            or self.rename_fields
         )