Fix demo url in readme

[nikitavbv]

Description

README.md contained the wrong URL for the UI Demo link. This change fixes that.

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This PR has:

• been tested to ensure log ingestion and log query works.
• added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
• added documentation for new or modified features or behaviors.

[nitisht]

Thanks @nikitavbv 👍🏽