Remove attempt to only enable the fixture when --json-report is used

It was actually not enabling it at all ever.

Author: asmeurer

conftest.py

@@ -2,7 +2,7 @@
 from pathlib import Path
 
 from hypothesis import settings
-from pytest import mark, fixture
+from pytest import mark
 
 from array_api_tests import _array_module as xp
 from array_api_tests._array_module import _UndefinedStub
@@ -126,6 +126,3 @@ def pytest_collection_modifyitems(config, items):
             ci_mark = next((m for m in markers if m.name == "ci"), None)
             if ci_mark is None:
                 item.add_marker(mark.skip(reason="disabled via --ci"))
-
-    if config.getoption('--json-report'):
-        fixture(autouse=True)(add_extra_json_metadata)

reporting.py

@@ -8,7 +8,7 @@
 
 from hypothesis.strategies import SearchStrategy
 
-from pytest import mark
+from pytest import mark, fixture
 try:
     import pytest_jsonreport # noqa
 except ImportError:
@@ -42,8 +42,7 @@ def pytest_metadata(metadata):
     metadata['array_api_tests_module'] = xp.mod_name
     metadata['array_api_tests_version'] = __version__
 
-# This is dynamically decorated as a fixture in pytest_collection_modifyitems
-# when --json-report is used.
+@fixture(autouse=True)
 def add_extra_json_metadata(request, json_metadata):
     """
     Additional per-test metadata for --json-report