Revert "feat(core): Add metric summaries to spans (#10432)"

[AbhiPrasad]

This reverts commit 94cdd8b.

I mistakenly merged this - we have to fix the metric summaries format.

Summaries are typed as pub type MetricSummaryMapping = Object<Array<MetricSummary>>;

Which means that the _metrics_summary type needs to be _metrics_summary?: Record<string, Array<MetricSummary>>;. This is because we need to create separate entries if the tags have changed.

"c:processor.item_processed": [
    {
        "min": 1,
        "max": 1,
        "count": 3,
        "sum": 3,
        "tags": {"success": true}
    },
    {
        "min": 1,
        "max": 1,
        "count": 2,
        "sum": 2,
        "tags": {"success": false}
    }
],