internal being appended to end of user search_path, even if it already includes internal

[MichaelBurgess]

Describe the bug
If a user provides a search_path that includes internal, internal is also being appended to the end of the search_path.

Steampipe version (steampipe -v)
Example: v0.19.5

To reproduce
Add a database options block with a valid (according to your connections) search_path such as:

options "database" {
  search_path = "public,foo,bar,internal"
}

Run steampipe query "show search_path;".

The output of the above is public,foo,bar,internal,internal.

The position of internal in the user search path doesn't matter - internal is always being appended to the end.

Expected behavior
The output of the above would be public,foo,bar,internal

Additional context
In Steampipe Cloud we append internal to the end of the search_path that we set.