BF: annotate tests in test_utils_cached_dataset with @skip_if_no_network

Since they all rely on access to a github repository ATM.
See #4653 for a possible RF to avoid that

datalad/tests/test_utils_cached_dataset.py

@@ -25,6 +25,7 @@
     assert_raises,
     assert_result_count,
     assert_true,
+    skip_if_no_network,
     with_tempfile
 )
 from unittest.mock import patch
@@ -34,6 +35,7 @@
 CLONE_PATCH_STR = "datalad.tests.utils_cached_dataset.Clone.__call__"
 
 
+@skip_if_no_network
 @with_tempfile(mkdir=True)
 def test_get_cached_dataset(cache_dir):
 
@@ -150,6 +152,7 @@ def test_get_cached_dataset(cache_dir):
             assert_is(ds, ds2)
 
 
+@skip_if_no_network
 @with_tempfile(mkdir=True)
 def test_cached_dataset(cache_dir):
 
@@ -250,6 +253,7 @@ def decorated_test4(ds):
         assert_not_equal(first_repopath, second_repopath)
 
 
+@skip_if_no_network
 @with_tempfile(mkdir=True)
 def test_cached_url(cache_dir):