Python: Fix planner notebook link to plan.py (#9486)

### Motivation and Context

Fix planner notebook link to plan.py file

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### Description

Fix planner notebook link to plan.py file.
- Closes #9041

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### Contribution Checklist

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- [X] The code builds clean without any errors or warnings
- [X] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
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script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [X] All unit tests pass, and I have added new tests where possible
- [X] I didn't break anyone 😄

python/samples/getting_started/05-using-the-planner.ipynb

@@ -270,7 +270,7 @@
    "source": [
     "To build more advanced planners, we need to introduce a proper Plan object that can contain all the necessary state and information needed for high quality plans.\n",
     "\n",
-    "To see what that object model is, look at (https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/planning/plan.py)\n"
+    "To see what that object model is, look at (https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/planners/plan.py)\n"
    ]
   },
   {
@@ -286,7 +286,7 @@
    "id": "a1c66d83",
    "metadata": {},
    "source": [
-    "The sequential planner is an XML-based step-by-step planner. You can see the prompt used for it [here](https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/planners/sequential_planner/Plugins/SequentialPlanning/skprompt.txt)\n"
+    "The sequential planner is an XML-based step-by-step planner. You can see the prompt used for it [here](https://github.com/microsoft/semantic-kernel/blob/main/python/semantic_kernel/planners/sequential_planner/Plugins/SequentialPlanning/skprompt.txt).\n"
    ]
   },
   {
@@ -567,7 +567,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3 (ipykernel)",
+   "display_name": "Python 3",
    "language": "python",
    "name": "python3"
   },
@@ -581,7 +581,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.12.3"
+   "version": "3.12.6"
   }
  },
  "nbformat": 4,