Python: Update skprompt.txt reference (#9307)

### Motivation and Context


### Description

Commit 5817c2b moved the location of
`skprompt.txt`. This PR adjusts sources to changes.

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [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)
and the [pre-submission formatting
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 😄

Signed-off-by: Emmanuel Ferdman <[email protected]>
Co-authored-by: Tao Chen <[email protected]>

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

@@ -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/planning/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"
    ]
   },
   {