remove unique lane check in sonic-mgmt (sonic-net#6487)

Summary: Duplicate lane check was added in sonic-utilities. Remove that in sonic-mgmt.
What is the motivation for this PR?
The GCU-related tests were bypassed in duplicate lanes' platforms. We don't want to skip GCU tests on such platforms.
So we update the unique lane check and simply bypass the check for such platforms in GCU feature.
Now the GCU tests can be tested on such platforms.

How did you do it?
Fix in GCU feature.
sonic-net/sonic-utilities#2343 has been updated to sonic-buildimage.

How did you verify/test it?
Run e2e test in specific platform.

tests/configlet/test_add_rack.py

@@ -27,21 +27,6 @@ def check_image_version(duthost):
     skip_release(duthost, ["201811", "201911", "202012", "202106", "202111"])
 
 
-@pytest.fixture(scope="module", autouse=True)
-def bypass_duplicate_lanes_platform(duthost):
-    """Skips platform that has duplicate lanes in default config
-
-    Args:
-        duthost: DUT host object.
-
-    Returns:
-        None.
-    """
-    if duthost.facts['platform'] == 'x86_64-arista_7050cx3_32s' or \
-            duthost.facts['platform'] == 'x86_64-dellemc_s5232f_c3538-r0':
-        pytest.skip("Temporary skip platform with duplicate lanes...")
-
-
 @pytest.fixture(autouse=True)
 def ignore_expected_loganalyzer_exceptions(duthost, loganalyzer):
     """

tests/generic_config_updater/conftest.py

@@ -13,14 +13,6 @@
 
 
 # Module Fixture
-@pytest.fixture(scope="module", autouse=True)
-def bypass_duplicate_lanes_platform(duthosts, rand_one_dut_hostname):
-    duthost = duthosts[rand_one_dut_hostname]
-    if duthost.facts['platform'] == 'x86_64-arista_7050cx3_32s' or \
-            duthost.facts['platform'] == 'x86_64-dellemc_s5232f_c3538-r0':
-        pytest.skip("Temporary skip platform with duplicate lanes...")
-
-
 @pytest.fixture(scope="module")
 def cfg_facts(duthosts, rand_one_dut_hostname):
     """