GCSDeleteObjectsOperator empty prefix bug fix

[Lavedonio]

closes: #24352
This PR solves the Issue #24352 for a bug found in GCSDeleteObjectsOperator, where an error was thrown if the parameter prefix was set to an empty string, which should be a valid input.

---

^ Add meaningful description above

Read the Pull Request Guidelines for more information.
In case of fundamental code change, Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragement file, named {pr_number}.significant.rst, in newsfragments.

[boring-cyborg]

Congratulations on your first Pull Request and welcome to the Apache Airflow community! If you have any issues or are unsure about any anything please check our Contribution Guide (https://github.com/apache/airflow/blob/main/CONTRIBUTING.rst)
Here are some useful points:

• Pay attention to the quality of your code (flake8, mypy and type annotations). Our pre-commits will help you with that.
• In case of a new feature add useful documentation (in docstrings or in docs/ directory). Adding a new operator? Check this short guide Consider adding an example DAG that shows how users should use it.
• Consider using Breeze environment for testing locally, it’s a heavy docker but it ships with a working Airflow and a lot of integrations.
• Be patient and persistent. It might take some time to get a review or get the final approval from Committers.
• Please follow ASF Code of Conduct for all communication including (but not limited to) comments on Pull Requests, Mailing list and Slack.
• Be sure to read the Airflow Coding style.
  Apache Airflow is a community-driven project and together we are making it better 🚀.
  In case of doubts contact the developers at:
  Mailing List: dev@airflow.apache.org
  Slack: https://s.apache.org/airflow-slack

[github-actions]

The PR is likely OK to be merged with just subset of tests for default Python and Database versions without running the full matrix of tests, because it does not modify the core of Airflow. If the committers decide that the full tests matrix is needed, they will add the label 'full tests needed'. Then you should rebase to the latest main or amend the last commit of the PR, and push it with --force-with-lease.

[potiuk]

Static checkes are failing

[Lavedonio]

Static checkes are failing

Just saw it right now. I can check that later today.

[Lavedonio]

All checks passed.

@turbaszek I think your review might also be needed in order to merge.

[eladkal]

@Lavedonio can you add test case with empty string to verify it works as expected and to avoid regression?

[Lavedonio]

Is anything else needed on my side?

[boring-cyborg]

Awesome work, congrats on your first merged pull request!

[potiuk]

@Lavedonio - just pinging when you'v done what you are asked for. Pushing an updated commit does not automatically mean information "I applied the fixes" - the best way to inform the maintainers is to ping them and mention it specifically that "you fixed it". You should be aware we have sometimes 30-50 conversation to look at a day - where you have just one PR. Watch my presentation here to understand more https://www.youtube.com/watch?v=G6VjYvKr2wQ

[Lavedonio]

@potiuk thanks for pointing that out. This is the first contribution that I've made to an open-source project, so I wasn't quite aware of how this final interaction worked. I'll make sure to watch your presentation later, thanks for the resource!