chore(codeowners): widen permissions for trace_handlers.py (#14294)

Right now updating an integration which uses the core api may also be
blocked on the sdk team since the integration handlers to convert core
events into spans lives in `ddtrace/_trace/`.

## Checklist
- [x] PR author has checked that all the criteria below are met
- The PR description includes an overview of the change
- The PR description articulates the motivation for the change
- The change includes tests OR the PR description describes a testing
strategy
- The PR description notes risks associated with the change, if any
- Newly-added code is easy to change
- The change follows the [library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
- The change includes or references documentation updates if necessary
- Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist
- [x] Reviewer has checked that all the criteria below are met 
- Title is accurate
- All changes are related to the pull request's stated goal
- Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes
- Testing strategy adequately addresses listed risks
- Newly-added code is easy to change
- Release note makes sense to a user of the library
- If necessary, author has acknowledged and discussed the performance
implications of this PR as reported in the benchmarks PR comment
- Backport labels are set in a manner that is consistent with the
[release branch maintenance
policy](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting)

Author: brettlangdon

.github/CODEOWNERS

@@ -193,6 +193,8 @@ tests/internal/remoteconfig         @DataDog/remote-config @DataDog/apm-core-pyt
 # API SDK
 ddtrace/trace/                                     @DataDog/apm-sdk-api-python
 ddtrace/_trace/                                    @DataDog/apm-sdk-api-python
+# File commonly updated for integrations, widen ownership to help with PR review
+ddtrace/_trace/trace_handlers.py                   @DataDog/apm-sdk-api-python @DataDog/apm-core-python @DataDog/apm-idm-python
 ddtrace/opentelemetry/                             @DataDog/apm-sdk-api-python
 ddtrace/internal/opentelemetry                     @DataDog/apm-sdk-api-python
 ddtrace/opentracer/                                @DataDog/apm-sdk-api-python