Consider updating tool for updating 3rd-party notices to be smarter about duplicates

[NikolaMilosavljevic]

Tool for updating TPN file, harvests notices from all dependent repos. It avoid duplicates, but still misses some harder-to-deduce cases. See this PR for examples: #74760

Explore options for updates in the tool or in baseline TPN files, so merging is easier and doesn't produce duplicates.

[NikolaMilosavljevic]

[Triage] Not needed anymore.