[BUG] Rds source getTableNames method requires REPLICATION priviledge

Describe the bug
Rds source requires Replication permission for non-replication operations.
For example, I see this error is:

org.opensearch.dataprepper.plugins.source.rds.schema.PostgresSchemaManager - Failed to get table names, retrying
org.postgresql.util.PSQLException: FATAL: permission denied to start WAL sender
 Detail: Only roles with the REPLICATION attribute may start a WAL sender process.
...
at org.opensearch.dataprepper.plugins.source.rds.schema.PostgresSchemaManager.getTableNames(PostgresSchemaManager.java:212)
...

The reason is that the rds source establish a replication connection to database to perform all needed operations, like get table names and schemas, stream CDC data, etc. However, some operations doesn't need a replication connection.
It shouldn't be an issue if the pipeline has stream enabled; but if a user only wants to do export, Replication permission (only needed for stream) shouldn't be required.

To Reproduce
Steps to reproduce the behavior:

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3. Scroll down to '....'
4. See error

Expected behavior
getTableNames method should only require SELECT permissions. We probably need to establish separate connection for non-replication operations.

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Environment (please complete the following information):

• OS: [e.g. Ubuntu 20.04 LTS]
• Version [e.g. 22]

Additional context
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