ci(redis): fix python<3.7 support (#7057)

Reverts the following commit:
80ff6f3.

Fixes the failing v1.20.2 build action:
https://github.com/DataDog/dd-trace-py/actions/runs/6314357914/job/17150041391.



## Checklist

- [x] Change(s) are motivated and described in the PR description.
- [x] Testing strategy is described if automated tests are not included
in the PR.
- [x] Risk is outlined (performance impact, potential for breakage,
maintainability, etc).
- [x] Change is maintainable (easy to change, telemetry, documentation).
- [x] [Library release note
guidelines](https://ddtrace.readthedocs.io/en/stable/releasenotes.html)
are followed. If no release note is required, add label
`changelog/no-changelog`.
- [x] Documentation is included (in-code, generated user docs, [public
corp docs](https://github.com/DataDog/documentation/)).
- [x] Backport labels are set (if
[applicable](https://ddtrace.readthedocs.io/en/latest/contributing.html#backporting))

## Reviewer Checklist

- [ ] Title is accurate.
- [ ] No unnecessary changes are introduced.
- [ ] Description motivates each change.
- [ ] Avoids breaking
[API](https://ddtrace.readthedocs.io/en/stable/versioning.html#interfaces)
changes unless absolutely necessary.
- [ ] Testing strategy adequately addresses listed risk(s).
- [ ] Change is maintainable (easy to change, telemetry, documentation).
- [ ] Release note makes sense to a user of the library.
- [ ] Reviewer has explicitly 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)
- [ ] If this PR touches code that signs or publishes builds or
packages, or handles credentials of any kind, I've requested a review
from `@DataDog/security-design-and-guidance`.
- [ ] This PR doesn't touch any of that.

Author: mabdinur

ddtrace/internal/compat.py

@@ -46,10 +46,6 @@
 PY2 = sys.version_info[0] == 2
 PY3 = sys.version_info[0] == 3
 
-try:
-    from unittest import mock
-except ImportError:
-    import mock  # type: ignore  # noqa
 
 try:
     from builtin import TimeoutError

tests/contrib/redis/test_redis.py

@@ -7,7 +7,6 @@
 from ddtrace.constants import ANALYTICS_SAMPLE_RATE_KEY
 from ddtrace.contrib.redis.patch import patch
 from ddtrace.contrib.redis.patch import unpatch
-from ddtrace.internal.compat import mock
 from ddtrace.internal.schema import DEFAULT_SPAN_SERVICE_NAME
 from tests.opentracer.utils import init_tracer
 from tests.utils import DummyTracer
@@ -17,6 +16,12 @@
 from ..config import REDIS_CONFIG
 
 
+try:
+    from unittest import mock
+except ImportError:
+    import mock  # type: ignore  # noqa
+
+
 class TestRedisPatch(TracerTestCase):
 
     TEST_PORT = REDIS_CONFIG["port"]