Allow adding metric to global metric trees during server initialization only

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    • Type: Task
    • Resolution: Unresolved
    • Priority: Major - P3
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      Each mongod and mongos has one global MetricTreeSet via globalMetricTreeSet(), which returns a reference to a process-wide StaticImmortal<MetricTreeSet>.

      • MetricTreeSet/MetricTree do not own a lock that serializes every mutator and reader on those trees.
      • The global trees are populated by MetricBuilder/ CustomMetricBuilder at file scope (startup). It does not enforce init-only registration.

      SERVER-123237 is making MetricsService::create* support registering OTEL metrics to the global MetricTreeSet for serverStatus reporting. Without adding a read/write mutex or some synchronization, OTEL metric creation would only be safe during initialization.

      The goal of this task is to add a `frozen` flag that will make metric addition assert if done after server initialization. All Otel metrics need to be added proactively during server initialization, before freezing.

            Assignee:
            Sergei Bazhenov
            Reporter:
            Cheahuychou Mao
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              Created:
              Updated: