Fabric Example pages linking to GitHub with incorrect format

Nobody has claimed this yet.

### 📚 Documentation

Go to this page in the Fabric docs: https://lightning.ai/docs/fabric/stable/examples/

Clicking the links for each of them pulls up a direct link to the GitHub page.

It seems that you want people to have access to the .py files on the GitHub page. Yes it works, but it jarring to the user and there is better way to do this instead of just linking to the GitHub page. Check out this page: https://lightning.ai/docs/app/stable/levels/basic/build_a_lightning_component.html

You did something similar to this:

.. lit_tabs::
:titles: Train using Fabric; Train using Pytorch
:code_files: ./examples/fabric/image_classifier/train_fabric.py; ./examples/fabric/image_classifier/train_pytorch.py
:highlights:
:enable_run: true
:tab_rows: 3
:height: 430px

cc @borda

Start with the Fabric examples page and compare its current links with the linked Build a Lightning Component page. Review the shown lit_tabs directive and the referenced train_fabric.py and train_pytorch.py examples, then update the rendered documentation so users can view or run the examples without being sent directly to GitHub.

Written by the indexing model from the issue text.