Remove redundant explicit grants from 999 SQL script

Summary

The 999_postgrest SQL file contains some explicit grants that follow a wildcard grant so they are completely redundant.

Is this a new feature?

• Yes, this is a new feature
• No, this is a change to existing functionality

Description of existing functionality

The R 999_postgrest SQL file contains the grant statements for web_anon user.

Recommended approach or architecture

Just delete them.