Keep Original minified React error in _meta

[AbhiPrasad]

Problem Statement

We want to make it more clear how Sentry is transforming error payloads, specifically for react minified errors. This is because it can be hard to tell how to filter these errors (using either beforeSend or server-side inbound filters) as the UI shows the transformed message, not the original one.

https://github.com/getsentry/relay/blob/master/relay-general/src/types/meta.rs

https://github.com/getsentry/sentry/blob/master/src/sentry/lang/javascript/errormapping.py

Solution Brainstorm

To address this, let's set the _meta field on processed events to add a remark that states that a substitution happened to the exception value. With this field, the UI can then explain to users how to filter errors.

• feat(utils): Add add_remark functionality to Meta class #44884
• feat(processor): Add meta field to react minified processor changes #45030
• Add message to event details page on how to use _meta