chore: fix e2e test using eastus2 region by default

[zhiying-lin]

What type of PR is this?

Fixes #

Requirements:

• run make reviewable for basic local test
• Read and followed fleet-networking's Code of conduct.
• uses conventional commit messages
• includes documentation
• adds unit tests

How has this code been tested

Special notes for your reviewer

[michaelawyu]

Not a blocking issue, though is it necessary to update the getting started tutorial as well?

[zhiying-lin]

Not a blocking issue, though is it necessary to update the getting started tutorial as well?
Yes, it's not necessary, prefer to change the default value together. :)