Fix add to sys path after cloning (#2849)

Fix
#2808 (comment)

If the notebook is launched after the OpenVoice repository has already
been cloned, the repository path might not be added to the system path.
The clone_repo function can handle this, so we only need to ensure that
openvoice/text/english.py is properly fixed.

Author: aleksandr-mokrov

notebooks/openvoice/openvoice.ipynb

@@ -109,8 +109,11 @@
     "\n",
     "repo_dir = Path(\"OpenVoice\")\n",
     "\n",
-    "if not repo_dir.exists():\n",
-    "    clone_repo(\"https://github.com/myshell-ai/OpenVoice\")\n",
+    "clone_repo(\"https://github.com/myshell-ai/OpenVoice\")\n",
+    "orig_english_path = Path(\"OpenVoice/openvoice/text/_orig_english.py\")\n",
+    "english_path = Path(\"OpenVoice/openvoice/text/english.py\")\n",
+    "\n",
+    "if not orig_english_path.exists():\n",
     "    orig_english_path = Path(\"OpenVoice/openvoice/text/_orig_english.py\")\n",
     "    english_path = Path(\"OpenVoice/openvoice/text/english.py\")\n",
     "\n",