refactor: f-string for tunneling.py

[nhankiet]

Description

Refactoring Python f-string format for tunneling.py

Please include:

• relevant motivation
• a summary of the change
• which issue is fixed.
• any additional dependencies that are required for this change.
  For better readability, shorter and code up-to-date with latest convention.
  No issue nor dependencies

Closes: # (issue)

Checklist:

• I have performed a self-review of my own code
• My code follows the style guidelines of this project
• I have commented my code in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[abidlabs]

Thanks @nhankiet for the contribution! I went ahead and ran our formatter on the changed file & will go ahead and merge this in shortly.