fix(aggregations, explain-plan): remove out stages before running explain plan COMPASS-7012 #4830
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We learned that non-genuine MongoDB servers, in particular CosmosDB, will execute pipelines when running explain plan even in
queryPlannermode. This is especially harmful when pipeline contains one of the out stages: $merge or $out. While we usually don't try to address compatibility issues like that with non-genuine servers, this one in particular can cause pretty bad data corruption issues, so we are fixing this by always removing out stages before running explain for aggregations for all servers. As a nice side-effect, this actually makes our visual explain plan more detailed for these kinds of pipelines.