test: flip global postage stamp usage in swarm extension

[nugaon]

we use POSTAGE_BATCH_ID for setting the used postage batch on Bee API requests in tests.

The problem with this approach it does not test out the production scenario as the personal storage writes should happen only if the global postage stamp is enabled in Swarm Extension.

The test environment setup script should be adjusted in a way to flip this global postage stamp on the Swarm Extension's page.