Disable monitoring in ML multinode tests

[williamrandolph]

Removing the deprecated "xpack.monitoring.enabled" setting introduced log spam and potentially some failures in ML tests. It's possible to use a different, non-deprecated setting to disable monitoring, so we do that here.

Relates #55420
Relates #54816

[elasticmachine]

Pinging @elastic/es-core-infra (:Core/Infra/Core)

[droberts195]

There is also a place in Java code where ML is disabling monitoring using the deprecated setting:

elasticsearch/x-pack/plugin/ml/qa/native-multi-node-tests/src/test/java/org/elasticsearch/xpack/ml/integration/MlNativeIntegTestCase.java

Line 135 in 92c8a73

builder.put(XPackSettings.MONITORING_ENABLED.getKey(), false);

Should that also be flipped over to using xpack.monitoring.elasticsearch.collection.enabled instead too?

In fact, if you search for usages of XPackSettings.MONITORING_ENABLED there are still about ten places in tests that use it to disable monitoring through Java code. Should they all be switched over?

[williamrandolph]

@droberts195 I was thinking of doing those in a follow-up PR but I'll go ahead and handle them here.

[droberts195]

I was thinking of doing those in a follow-up PR

@williamrandolph if you think there's a risk of breaking other things then a follow-up PR is fine with me.

LGTM for the changes so far.

[benwtrent]

seems good to me :)

[williamrandolph]

Backported to 7.x: 7817948