Connect to Aiven for PostgreSQL documentation - Step 3 wording

### Version Information

Issue is in the document https://hasura.io/docs/latest/graphql/cloud/getting-started/cloud-databases/aiven.html

### Environment

### What is the expected behaviour?

Step 3 is technically not required since Aiven for PostgreSQL is publicly available by default. However Limiting the IP ranges is a good suggestion. Changing the wording might be needed.

### Keywords

Aiven

### What is the current behaviour?

The current title "Step 3: Allow connections to your DB from Hasura Cloud" makes people think it's to allow connection, while, in reality is to restrict

### How to reproduce the issue?

The issue is in the doc

### Screenshots or Screencast

### Please provide any traces or logs that could help here.

### Any possible solutions?

### Can you identify the location in the source code where the problem exists?

### If the bug is confirmed, would you be willing to submit a PR?

Open the linked Aiven for PostgreSQL documentation and review Step 3's title and wording. Clarify that public access is already enabled by default and that limiting IP ranges is an optional security recommendation; the work is done when the step no longer implies it is required to allow the connection.

Written by the indexing model from the issue text.