Fix platform.system() checking (#2775)

CVS-161264

Author: aleksandr-mokrov

notebooks/tensorflow-quantization-aware-training/tensorflow-quantization-aware-training.ipynb

@@ -75,7 +75,7 @@
     "import platform\n",
     "\n",
     "\n",
-    "if platform.system() == \"darwin\" and platform.processor() in (\"arm\", \"arm64\"):\n",
+    "if platform.system() == \"Darwin\" and platform.processor() in (\"arm\", \"arm64\"):\n",
     "    %pip uninstall -qy tensorflow\n",
     "\n",
     "%pip install -q \"openvino>=2024.6.0\" \"nncf>=2.14.0\"\n",