Fixed ActivationTypeIT flakyness

[JonasKunz]

What does this PR do?

The agent does not sent the activation method when a APM server older than 8.7.1 is detected.
This caused some flakyness in the AgentActivationIT: If the health-check request finished before the metadata is generated, the agent assumed a pre-6.0 apm server and therefore did not send the activation method.
If the apm-server version is not known (the health-check request did not finish yet), the activation method is sent.

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• Start Time: 2023-04-06T09:01:36.896+0000

• Duration: 14 min 5 sec

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