Add Histograms to Dashboards

### Problem Statement

I present performance metrics from Sentry to engineering executives, and I encountered challenges in effectively illustrating the distribution of user experiences. Currently, executives tend to rely on `avg` performance metrics to gauge application performance, often comparing these figures to their own experience. However, this approach can be misleading, as the `avg` may not accurately represent the full range of user interactions.

### Solution Brainstorm

Introducing histogram visualizations would allow for a clearer representation of the distribution across different percentiles of user experiences. This enhancement would empower teams to better understand performance variability, enabling more accurate assessments of user impact and alignment with internal benchmarks.

Currently the diagram is available only for web vitals (Transaction Summary -> Web Vitals) the ask is to add it to Dashboards with the ability to customize custom metrics.


### Product Area

Dashboards

Start by reviewing the existing histogram in Transaction Summary → Web Vitals and how Dashboards handle custom metrics. The work is complete when equivalent histogram visualizations are available in Dashboards with configurable custom metrics and the distribution is represented across percentiles.

Written by the indexing model from the issue text.