`http.response.status_code` normalization for Metrics & Alerts

[kahest]

Background:

http.status is set in different places in different SDKs which creates some problems in processing for metrics extraction and then

https://www.notion.so/sentry/Expand-Metrics-for-Alerts-cdfa32d7624e498b8246c3f131f753f1#17480955e2fb4407b619b9236bc2723a

Requirements:

• Need status code number (standard HTTP status code 2xx, 4xx, 5xx, etc)
• The SDK should never on it's own set this as a tag - as this adds expense due to indexing being based on tags
• the location of storage needs to be in a standard location based on span schema
  • follow existing standard in develop docs
  • of not starfish has a workstream to standardize span schema rfc(feature): Aligning the Span Schema with OpenTelemetry rfcs#89

Note: .NET and Java are handled in getsentry/team-sdks#9.

### Validate Per SDK and check as is
- [ ] https://github.com/getsentry/sentry-cocoa/issues/3076
- [ ] https://github.com/getsentry/sentry-dart/issues/1473
- [x] https://github.com/getsentry/sentry-java/pull/2786
- [x] React Native

[romtsn]

We'll look into the code base and check if anything has to be done and check off the platform if nothing is needed.

[marandaneto]

@antonpirker this doc is related to this issue right?
We just need to be sure what the schema is, so we can double-check in our implementation.

[marandaneto]

https://develop.sentry.dev/sdk/performance/span-operations/ does not tell where http.status should go.
getsentry/rfcs#89 is a draft and it links to OTel which is a huge breaking change.

[marandaneto]

getsentry/develop#940 is the spec, I believe SDKs don't set that yet, so we have to.