GA network policies (#32029)

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### Checklist

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Author: sjwiesman

doc/user/content/manage/access-control/manage-network-policies.md

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-{{< private-preview />}}
-
 {{< tip >}}
 We recommend using [Terraform](https://registry.terraform.io/providers/MaterializeInc/materialize/latest/docs/resources/network_policy)
 to configure and manage network policies.

doc/user/content/sql/alter-network-policy.md

@@ -6,8 +6,6 @@ menu:
     parent: commands
 ---
 
-{{< private-preview />}}
-
 `ALTER NETWORK POLICY` alters an existing network policy. Network policies are
 part of Materialize's framework for [access control](/manage/access-control/).
 

doc/user/content/sql/create-network-policy.md

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     parent: commands
 ---
 
-{{< private-preview />}}
-
 `CREATE NETWORK POLICY` creates a network policy that restricts access to a
 Materialize region using IP-based rules. Network policies are part of
 Materialize's framework for [access control](/manage/access-control/).

doc/user/content/sql/drop-network-policy.md

@@ -6,8 +6,6 @@ menu:
     parent: commands
 ---
 
-{{< private-preview />}}
-
 `DROP NETWORK POLICY` removes an existing network policy from Materialize.
 Network policies are part of Materialize's framework for [access control](/manage/access-control/).