Avoid re snapshot for DDL that will not change the underlying table

[altmannmarcelo]

Description

There are some operations which do not change the underlining table structure related to Readyset (number of columns, data types). Those can skip snapshot.

readyset> ALTER TABLE category ADD INDEX (name);
Query OK, 0 rows affected (4,077 sec)

2025-06-03T17:13:33.508088Z  INFO replicators::noria_adapter: Change in DDL requires partial resnapshot
2025-06-03T17:13:36.526229Z  INFO taking database snapshot: replicators::noria_adapter: Starting snapshot

Change in user-visible behavior

Requires documentation change