chore(sampling_rules): remove support for regex and callable matchers

[mabdinur]

With ddtrace v3.0 sampling rules only support glob matching. This PR removes the deprecated callable and regex pattern matchers. These matchers are internal to the ddtrace library and are unused. So we can remove them in a minor version.

Checklist

• 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
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• 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 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

[github-actions]

CODEOWNERS have been resolved as:

ddtrace/_trace/sampler.py                                               @DataDog/apm-sdk-api-python
ddtrace/_trace/sampling_rule.py                                         @DataDog/apm-sdk-api-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 277 ± 2 ms.

The average import time from base is: 279 ± 2 ms.

The import time difference between this PR and base is: -1.99 ± 0.09 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 2.003 ms (0.72%)

ddtrace.bootstrap.sitecustomize 1.329 ms (0.48%)

ddtrace.bootstrap.preload 1.329 ms (0.48%)

ddtrace.internal.remoteconfig.client 0.661 ms (0.24%)

ddtrace 0.674 ms (0.24%)

ddtrace.internal._unpatched 0.029 ms (0.01%)

json 0.029 ms (0.01%)

json.decoder 0.029 ms (0.01%)

re 0.029 ms (0.01%)

enum 0.029 ms (0.01%)

types 0.029 ms (0.01%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-07-14 18:16:59

Comparing candidate commit dc93da6 in PR branch munir/sampling-remove-unused-code with baseline commit e0a772c in branch main.

Found 0 performance improvements and 3 performance regressions! Performance is the same for 485 metrics, 2 unstable metrics.

scenario:iastaspects-format_map_aspect

• 🟥 execution_time [+411.926ns; +493.363ns] or [+12.831%; +15.368%]

scenario:iastaspects-replace_aspect

• 🟥 execution_time [+712.208ns; +782.368ns] or [+14.959%; +16.433%]

scenario:iastaspectsospath-ospathsplit_aspect

• 🟥 execution_time [+944.747ns; +1035.164ns] or [+19.301%; +21.148%]