Re-enable test_dockerfile_can_contain_custom_kfp_package

Removed the skip unit test decorator that was previously added to bypass the test due to failure (referencing issue #11038).

The issue reported in #11038 was caused due to the Dockerfile referencing to Python 3.7. With the Python version updated to 3.9, the test now passes consistently.
This commit re-enables the test to ensure proper validation of Dockerfile creation and KFP package.

Signed-off-by: ddalvi <ddalvi@redhat.com>

sdk/python/kfp/cli/component_test.py

@@ -579,9 +579,6 @@ def test_existing_dockerfile_can_be_overwritten(self):
                 COPY . .
                 '''))
 
-    @unittest.skip(
-        "Skipping this test as it's failing. Refer to https://github.com/kubeflow/pipelines/issues/11038"
-    )
     def test_dockerfile_can_contain_custom_kfp_package(self):
         component = _make_component(
             func_name='train', target_image='custom-image')
@@ -608,7 +605,7 @@ def test_dockerfile_can_contain_custom_kfp_package(self):
         file_start = textwrap.dedent('''\
                 # Generated by KFP.
 
-                FROM python:3.9
+                FROM python:3.12
 
                 WORKDIR /usr/local/src/kfp/components
                 COPY runtime-requirements.txt runtime-requirements.txt