Fix race conditions in our template tests

[FranjoMindek]

Currently, our templates e2e tests can fail due to race conditions.
Once such race condition is around updating user's subscription status in time before we read and test the user's subscription status.

This one was recorded by me:

1. invoice.paid webhook event sent timestamp - 2:24:58

2. Backend reacting to the invoice.paid event and updating the subscription status: 2:25:07

3. Client reading the user's subscription status on the Account page: 2:25:05

This results in us failing the e2e-tests.

[cprecioso]

Link to failing CI run: https://github.com/wasp-lang/open-saas/actions/runs/21027744847/job/60456195514?pr=600