Fix examples exploration link 404 by removing path segment artifact

[shokrydev]

Fixes #21445.

Removes the path segment artifact "/lightning-ai", as proposed in #21445.

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📚 Documentation preview 📚: https://pytorch-lightning--21446.org.readthedocs.build/en/21446/

[bhimrazy]

Suggested change

	Define the training workflow. Here's a toy example ([explore real examples](https://lightning.ai/studios?view=public&section=featured&query=pytorch+lightning&utm_source=ptl_readme&utm_medium=referral&utm_campaign=ptl_readme)):
	Define the training workflow. Here's a toy example ([explore real examples](https://lightning.ai/environments?view=public&section=featured&query=pytorch+lightning&utm_source=ptl_readme&utm_medium=referral&utm_campaign=ptl_readme)):

Maybe we should also update “studios” to “environments” here, since that’s the new link and avoids the redirection.