Remove waiting for the next block in e2e tests

[zivkovicmilos]

Description

This PR fixes a minor testing issue, where tests would assume transactions are contained in the next block, when that doesn't have to be the case, and thus causing GH actions to sometimes fail.

Changes include

• Bugfix (non-breaking change that solves an issue)
• Hotfix (change that solves an urgent issue, and requires immediate attention)
• New feature (non-breaking change that adds functionality)
• Breaking change (change that is not backwards-compatible and/or changes current functionality)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels
• I have updated the official documentation
• I have added sufficient documentation in code

Testing

• I have tested this code with the official test suite
• I have tested this code manually

[0xAleksaOpacic]

LGTM! Thank you for improving our test suite!

[Kourin1996]

@zivkovicmilos When I run tests several times locally and I always saw same error. Can you run test locally?

--- FAIL: TestPoS_UnstakeExploit (11.10s)
    pos_test.go:401: unable to wait for receipts, [unable to wait for receipt, timeout unable to wait for receipt, timeout unable to wait for receipt, timeout unable to wait for receipt, timeout]
FAIL

[zivkovicmilos]

@Kourin1996

Located the problem with the gas limit in the test.

Fixed 👍

5200166

[Kourin1996]

LGTM