[CWS] send signal event when targeting multiple processes

[spikat]

What does this PR do?

Motivation

Be able to detect signal sent with 0 or -1 as pid kill argument. In this case, target process will not be resolved.

Describe how you validated your changes

Possible Drawbacks / Trade-offs

Additional Notes

[agent-platform-auto-pr]

[Fast Unit Tests Report]

On pipeline 50975761 (CI Visibility). The following jobs did not run any unit tests:

Jobs:

• tests_deb-arm64-py3
• tests_deb-x64-py3
• tests_flavor_dogstatsd_deb-x64
• tests_flavor_heroku_deb-x64
• tests_flavor_iot_deb-x64
• tests_rpm-arm64-py3
• tests_rpm-x64-py3
• tests_windows-x64

If you modified Go files and expected unit tests to run in these jobs, please double check the job logs. If you think tests should have been executed reach out to #agent-devx-help

[agent-platform-auto-pr]

Package size comparison

Comparison with ancestor 8ca1369d2b6deeee0c640ce05dfe2c38186b61d5

Diff per package

package	diff	status	size	ancestor	threshold
datadog-agent-amd64-deb	-0.01MB	✅	1271.25MB	1271.25MB	140.00MB
datadog-iot-agent-amd64-deb	0.00MB	✅	113.20MB	113.20MB	10.00MB
datadog-dogstatsd-amd64-deb	0.00MB	✅	78.32MB	78.32MB	10.00MB
datadog-heroku-agent-amd64-deb	0.00MB	⚠️	526.44MB	526.44MB	70.00MB
datadog-agent-x86_64-rpm	-0.01MB	✅	1280.48MB	1280.49MB	140.00MB
datadog-agent-x86_64-suse	-0.01MB	✅	1280.48MB	1280.49MB	140.00MB
datadog-iot-agent-x86_64-rpm	0.00MB	✅	113.27MB	113.27MB	10.00MB
datadog-iot-agent-x86_64-suse	0.00MB	✅	113.27MB	113.27MB	10.00MB
datadog-dogstatsd-x86_64-rpm	0.00MB	✅	78.40MB	78.40MB	10.00MB
datadog-dogstatsd-x86_64-suse	0.00MB	✅	78.40MB	78.40MB	10.00MB
datadog-agent-arm64-deb	0.01MB	⚠️	1005.43MB	1005.42MB	140.00MB
datadog-iot-agent-arm64-deb	0.00MB	✅	108.70MB	108.70MB	10.00MB
datadog-dogstatsd-arm64-deb	0.00MB	✅	55.59MB	55.59MB	10.00MB
datadog-agent-aarch64-rpm	0.01MB	⚠️	1014.64MB	1014.64MB	140.00MB
datadog-iot-agent-aarch64-rpm	0.00MB	✅	108.77MB	108.77MB	10.00MB

Decision

⚠️ Warning