PYCBC-1729: Skip tracing and metrics tests until new observability

changes are complete

Motivation
==========
The underlying C++ core changes related to observability improvements
(CBD-6492) are blocking CI runs from passing as the old tracing/metrics
tests are failing.  The improvement work for updating how observability
is handled in the Python client is underway so these tests will
eventually be improved/updated.  Skipping the tests in the interim will
allow other work on the Python client to continue.

Modification
============
* Skip all tests w/in ClassicMetricsTests and ClassTracingTests

Results
=======
* CI runs no longer blocked by failing tracing/metrics tests

Change-Id: Ie8343f2999d35931d0ed3f5f11e3333faa368be6
Reviewed-on: https://review.couchbase.org/c/couchbase-python-client/+/236877
Reviewed-by: Dimitris Christodoulou <dimitris.christodoulou@couchbase.com>
Tested-by: Build Bot <build@couchbase.com>

Author: thejcfactor

couchbase/tests/metrics_t.py

@@ -88,6 +88,7 @@ def test_custom_logging_meter_kv(self, cb_env, op):
     #     cb_env.meter.reset()
 
 
+@pytest.mark.skip(reason='Skip until new observability changes drop (CBD-6492)')
 class ClassicMetricsTests(MetricsTestSuite):
     @pytest.fixture(scope='class')
     def test_manifest_validated(self):

couchbase/tests/tracing_t.py

@@ -116,6 +116,7 @@ def test_http(self, cb_env, http_op, http_span_name, http_opts, query, extra, ht
         assert spans[0].get_parent() == parent
 
 
+@pytest.mark.skip(reason='Skip until new observability changes drop (CBD-6492)')
 class ClassicTracerTests(TracerTestsSuite):
     @pytest.fixture(scope='class')
     def test_manifest_validated(self):