Address invalid monitoring configuration that prevents Elasticsearch from starting

[jakelandis]

This implementation is sufficient becuase

• It generically solves the cluster state application across all of
  the settings by catching the exception and logging it.

This implementation is not ideal becuase

• It allow invalid configuration to be persisted to cluster state,
  with only a message to the log
• Does not notify the user that the configuration maybe incorrect
  via the REST API.

To notify the the user that the configuration is incorrect via the
REST API and prevent persisting config to cluster state, one would
need to implement a validator via
clusterService.getClusterSettings().addAffixUpdateConsumer(HOST_SETTING , consumer, validator)

However, this is not done becuase

• It requires calling initExporters to find any exceptions that may be found.
  • Calling initExporters is not feasible due to
    • It would require alot of work on cluster update (even if we
      refactored out the validation bits)
    • We don't have easy access to the set of settings that are currently
      being set, just easy access to the single setting. This is an affix
      setting with other highly correlated settings needed to determine
      correctness. The validator sees settings 1 by 1, not the full set
      of settings being set.
    • On node startup this validation is also run, so if by some means
      [1] invalid config got into cluster state the exception would be thrown
      to the cluster state applier, not the REST layer.
• HOST_SETTINGS is not unique in it's behavior here. For example
  xpack.monitoring.exporters.foo.use_ingest will exibit the same behavior
  if foo has not been defined.

Fixes #47125

EDIT: removed an incorrect statement

[jakelandis]

closing in favor of #47246