Migrate mock_http fixture and test files to MockHTTPResponse

[mwdd146980]

What does this PR do?

Remaining changes from the httpx migration feature branch (#22676), split out from the base modules PR (mwdd146980/base-http-modules).

Includes:

• mock_http fixture in datadog_checks_dev (pytest plugin)
• AgentCheck.http property update for mock_http support
• MockResponse → MockHTTPResponse migration across ~40 test files
• vault and traefik_mesh production code updates
• OpenMetrics scraper updates for http_protocol compatibility

Motivation

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[datadog-datadog-prod-us1-2]

⚠️ Tests

✨ Fix all issues with BitsAI or with Cursor

⚠️ Other Violations

🧪 1 Test failed

test_e2e_snmp_listener from test_e2e_snmp_listener.py     (Fix with Cursor)

Needed at least 1 candidates for 'datadog.snmp.check_duration', got 0
Expected:
        MetricStub(name='datadog.snmp.check_duration', type=0, value=None, tags=['autodiscovery_subnet:172.18.0.0/28', 'device_vendor:apc', 'firmware_version:2.0.3-test', 'loader:python', 'model:APC Smart-UPS 600', 'serial_num:test_serial', 'snmp_device:172.18.0.1', 'snmp_profile:apc_ups', 'ups_name:testIdentName'], hostname=None, device=None, flush_first_value=None)
Difference to closest:
        Expected tag snmp_device:172.18.0.1
        Found snmp_device:172.18.0.2

Similar submitted:
Score   Most similar
1.00    MetricStub(name='datadog.snmp.check_duration', type=0, value=0.2171943187713623, tags=['autodiscovery_subnet:172.18.0.0/28', 'device_vendor:apc', 'firmware_version:2.0.3-test', 'loader:python', 'model:APC Smart-UPS 600', 'serial_num:test_serial', 'snmp_device:172.18.0.2', 'snmp_profile:apc_ups', 'ups_name:testIdentName'], hostname='runnervmtxuyr', device=None, flush_first_value=False)
...

ℹ️ Info

No other issues found (see more)

❄️ No new flaky tests detected

🎯 Code Coverage (details)
• Patch Coverage: 98.30%
• Overall Coverage: 87.04% (+0.02%)

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 5039185 | Docs | Datadog PR Page | Was this helpful? React with 👍/👎 or give us feedback!}

[codecov]

Codecov Report

❌ Patch coverage is 98.29545% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.59%. Comparing base (6686cd3) to head (5039185).

Additional details and impacted files

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[dd-octo-sts]

Validation Report

Validation	Status
agent-reqs	✅
ci	✅
codeowners	✅
config	✅
dep	✅
http	✅
imports	✅
integration-style	✅
jmx-metrics	✅
labeler	✅
legacy-signature	✅
license-headers	✅
licenses	✅
metadata	✅
models	✅
openmetrics	✅
package	✅
readmes	✅
saved-views	✅
version	✅

View full run

[mwdd146980]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Migrate conftest.py MockResponse fixture chains to MockHTTPResponse #23226
• Batch migrate integration tests from MockResponse to MockHTTPResponse #23207
• Widen production except clauses for httpx migration #23046
• Migrate mock_http fixture and test files to MockHTTPResponse #23300 👈 (View in Graphite)
• Add HTTP protocol types, exception hierarchy, and MockHTTPResponse #23299
• master

This stack of pull requests is managed by Graphite. Learn more about stacking.