[BUG] FleetDispatchAttackTest is flaky and fails sometimes

[lanedirt]

Describe the bug
The following test fails sometimes when it runs against new PR's.

FAILED  Tests\Feature\FleetDispatch\FleetDispatchAttackTest > dispatch fl…   
  Defender still has same amount of metal after battle while it was expected they lost some.
Failed asserting that OGame\Models\Resource Object #11716 (
    'rawValue' => 240.0,
) is less than OGame\Models\Resource Object #8544 (
    'rawValue' => 240.0,
).

Check the test logic and change it so its not flaky anymore. This test logic tests the battle engine which results are random by nature, so this test will have to be updated so the chance that the test has it wrong is less likely (near zero). Alternatively these battle engine tests should implement a retry logic.

[lanedirt]

This issue was fixed as part of PR #514. The test has been rewritten to use a new (clean) planet as the target instead of an existing planet, as sometimes an existing planet had other active missions flying towards it which skewed the expected results.