update pg_dump version: 16.11 to 17.7

I'm running into the same issue that was brought up here:
https://github.com/Azure/CloudShell/issues/383

Our Azure PostgreSQL Flexible Servers are on 17.7 and Azure Cloud Shell is using 16.11

This Azure post states that Azure PostgreSQL Flexible Servers support the following versions.

https://azure.microsoft.com/en-us/updates?id=550164
"PostgreSQL minor versions 18.1, 17.7, 16.11, 15.15, 14.20, and 13.23 are now supported by Azure Database for PostgreSQL – Flexible Server."

We need Azure Cloud Shell to support the same versions of PostgreSQL as Azure PostgreSQL Flexible Server supports.

This will allow us to use automations for backup/restore operations.

I understand that Cloud Shell is based on Azure Linux 3.0, however there isn't any reason that Azure Linux 3.0 cannot be updated to match Azure Database for PostgreSQL – Flexible Server supported versions.