[FLINK-31567][release] Add 1.17 to previous doc list

[PatrickRen]

What is the purpose of the change

This pull request add 1.17 to previous docs list, so that the doc on master branch can show 1.17 in the "Pick Docs Version" section on the nav sidebar.

Brief change log

• Add 1.17 to previous doc list in config.toml

Verifying this change

The change is verified locally by previewing the doc with Hugo.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

CI report:

• 97ae8bf Azure: PENDING

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[leonardBang]

Thanks @PatrickRen for the fix, LGTM