Add info about JSON Connection format for AWS SSM Parameter Store Secrets Backend

[Taragolis]

Since Airflow 2.3 Connection could be represented as JSON object which perfectly work without any changes in SystemsManagerParameterStoreBackend.get_conn_value

• Add appropriate info in AWS SSM Parameter Store Secrets Backend doc
• Add tests that it actually works with SSM Parameter Store SB (also helps if something changed in the future)
• Add changes in deprecated method SystemsManagerParameterStoreBackend.get_conn_uri so it return always URI even if it stored as JSON objects. I do not know but might be better just remove this method since it should not use internally in Airflow since 2.3 however it might use in some user code.

[vincbeck]

Is it me or the sentence In some cases, URI's you will need stored in AWS SSM Parameter Store may not be intuitive does not make a lot of sense ?

[Taragolis]

Good point to change it. If it confuse you than it might confuse others.
From my side I've just change "Secrets Manager" to "AWS SSM Parameter Store" and split long line.

[vincbeck]

Nice. I would make it even simpler.

In some cases, URIs stored in AWS SSM Parameter Store may not be intuitive,

[Taragolis]

I thought that initial author tried to highlight that Airflow connection URI not a specific connection URI.

E.g. user expected that HTTP https://example.org/path would work however in Airflow we should use http://https%3A%2F%2Fexample.org%2Fpath

There is also a link to example how to generate URI exists in current doc: https://airflow.apache.org/docs/apache-airflow/stable/howto/connection.html#generating-connection-uri

[potiuk]

Any more comments here :) ?

[Taragolis]

Any more comments here :) ?

I've just add reuse same pytest parameters in different tests cases