Add HTTPXWrapper backed by httpx2

[mwdd146980]

What does this PR do?

Adds an HTTPXWrapper backed by httpx2 behind a use_httpx instance config flag. The default remains RequestsWrapper. Also widens the OpenMetrics v2 scraper to catch HTTPConnectionError alongside requests.exceptions.ConnectionError.

Motivation

Design validation for the migration RFC. httpx2 is the Pydantic-maintained successor to httpx, picking up stewardship now that the upstream project has slowed. Landing on a maintained library before any integration opts in. Supersedes the design exercise in #23822, which targeted httpx itself.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add `qa/required` if this PR needs QA validation, or `qa/skip-qa` if it does not. Exactly one of the two is required.
• If you need to backport this PR to another branch, you can add the `backport/` label to the PR and it will automatically open a backport PR once this one is merged

---

This PR has been created and validated using the paired-review skill from agent-integrations. Ready for human review.

[datadog-prod-us1-6]

 

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 9 Pipeline jobs failed

PR All | test / jcc7e1d2 / Nutanix     

🔧 Fix in code (Fix with Cursor).

3 undefined names: 'mock_resp' and 'mocker' in tests/conftest.py at lines 166 and 167.

PR All | test / j06ca546 / SNMP     

🔄 Retry job. This looks flaky and may succeed on retry.

Failed to resolve 'ddintegrations.blob.core.windows.net'. NameResolutionError occurred during HTTP requests.

PR All | test / j46da136 / JBoss_WildFly     

🔄 Retry job. This looks flaky and may succeed on retry.

Could not resolve hostname 'ddintegrations.blob.core.windows.net:443'.

View all 9 failed jobs.

🧪 20 Tests failed in 1 job

PR All | run  

test_bulk_table from test_check.py   (Fix with Cursor)

HTTPSConnectionPool(host='ddintegrations.blob.core.windows.net', port=443): Max retries exceeded with url: /snmp/cisco-3850.snmprec (Caused by NameResolutionError("HTTPSConnection(host='ddintegrations.blob.core.windows.net', port=443): Failed to resolve 'ddintegrations.blob.core.windows.net' ([Errno -2] Name or service not known)"))

test_cast_metrics from test_check.py   (Fix with Cursor)

HTTPSConnectionPool(host='ddintegrations.blob.core.windows.net', port=443): Max retries exceeded with url: /snmp/cisco-3850.snmprec (Caused by NameResolutionError("HTTPSConnection(host='ddintegrations.blob.core.windows.net', port=443): Failed to resolve 'ddintegrations.blob.core.windows.net' ([Errno -2] Name or service not known)"))

View all 20 test failures

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 94.73%
• Overall Coverage: 87.97% (+0.53%)

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[dd-octo-sts]

Validation Report

Validation	Description	Status
dep	Verify dependency pins are consistent and Agent-compatible	❌
qa-label	Validate the pull request declares whether it needs QA for the next Agent release	❌

Run ddev validate all changed --fix to attempt to auto-fix supported validations.

Passed validations (19)

Validation	Description	Status
agent-reqs	Verify check versions match the Agent requirements file	✅
ci	Validate CI configuration and Codecov settings	✅
codeowners	Validate every integration has a CODEOWNERS entry	✅
config	Validate default configuration files against spec.yaml	✅
http	Validate integrations use the HTTP wrapper correctly	✅
imports	Validate check imports do not use deprecated modules	✅
integration-style	Validate check code style conventions	✅
jmx-metrics	Validate JMX metrics definition files and config	✅
labeler	Validate PR labeler config matches integration directories	✅
legacy-signature	Validate no integration uses the legacy Agent check signature	✅
license-headers	Validate Python files have proper license headers	✅
licenses	Validate third-party license attribution list	✅
metadata	Validate metadata.csv metric definitions	✅
models	Validate configuration data models match spec.yaml	✅
openmetrics	Validate OpenMetrics integrations disable the metric limit	✅
package	Validate Python package metadata and naming	✅
readmes	Validate README files have required sections	✅
saved-views	Validate saved view JSON file structure and fields	✅
version	Validate version consistency between package and changelog	✅

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[codecov]

Codecov Report

❌ Patch coverage is 94.72817% with 32 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (mwdd146980/httpx-migration-base@f14a5ce). Learn more about missing BASE report.

Additional details and impacted files

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