Fix `accessor` name changes

[rekhoff]

This is a follow up action from a comment on #5145 that reads::

joshua-spacetime:
This renames the table accessor too. We're migrating st_index_accessor, but what about st_table_accessor?

Shubham8287:
I think I should fix accessor name changes in separate PR, as that change requires more thorough considerations.

I am keeping the current PR to fix building correct IndexSchema from sys tables, Which will unblock the table migration path. As people will run into table migration more frequently than changing accessor name especially during Hackothon