[kedro-airflow] Update `kedro-airflow` to take in custom session id

## Description
To be done after https://github.com/kedro-org/kedro/issues/1731

## Context
https://github.com/kedro-org/kedro/issues/1551

It was decided to allow users to customise the `session_id` which would make it easier when using an orchestrator like Airflow to map airflow runs to kedro runs and versioned datasets.

Start by reviewing Kedro issues #1731 and #1551, then inspect the kedro-airflow plugin's handling of session_id. Determine where a custom session ID can be accepted so Airflow runs map to Kedro runs and versioned datasets; done means the requested customization is supported and verified by the relevant plugin tests.

Written by the indexing model from the issue text.