[FLINK-27890][examples] Fix the bug introduced By [FLINK-19317] to use the return result after assignTimestampsAndWatermarks

[coderappee]

What is the purpose of the change

Fix the SideOutputExample bug introduced by [FLINK-19317].

Brief change log

• Use the return result after assign the TimestampsAndWatermarks for the next step

Verifying this change

Please make sure both new and modified tests in this PR follows the conventions defined in our code quality guide: https://flink.apache.org/contributing/code-style-and-quality-common.html#testing

This change is a trivial rework / code cleanup without any test coverage.

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

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

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

[flinkbot]

CI report:

• b96393c Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

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

[alpinegizmo]

@coderappee You've ended up with two apparently identical commits in this PR. Could you clean that up, please?

[coderappee]

@coderappee You've ended up with two apparently identical commits in this PR. Could you clean that up, please?

Could you tell me how to do it? Close this pull request and then roll back the last two commit and recommit again?

[reswqa]

@coderappee You've ended up with two apparently identical commits in this PR. Could you clean that up, please?

Could you tell me how to do it? Close this pull request and then roll back the last two commit and recommit again?

Squash the two commits to one, and force push to you own repo branch coderappee:FLINK-27890,it will update this pull request automatically.

[alpinegizmo]

@coderappee Let me know if you're stuck, and I can take care of this when I merge the PR.

In this particular situation, it should be enough to rollback the last commit in your branch and then force push to the branch in your fork that is the basis for this PR.

[coderappee]

@coderappee Let me know if you're stuck, and I can take care of this when I merge the PR.

In this particular situation, it should be enough to rollback the last commit in your branch and then force push to the branch in your fork that is the basis for this PR.

I rollback the last commit, then use "git commit --amend" to add some changes to last second commit, and then force push to the branch for this PR.
I do not know it is ok or not.

[coderappee]

@flinkbot run azure

[alpinegizmo]

Thank you @coderappee for your contribution!

[alpinegizmo]

Merged in master with a70e704
Merged in release-1.15 with 6fcec2c