Fix PointListReader for reading single-element (Point1D case) per line

[Seangongx]

PR Description

• Fixed the failure when give the extreme input case by single-element(Like typedef DGtal::PointVector<1, DGtal::int32_t> Point1D) using getPolygonsFromInputStream() function.
• Changed the sample data and added new test.

Checklist

• Unit-test of your feature with Catch.
• Doxygen documentation of the code completed (classes, methods, types, members...)
• Documentation module page added or updated.
• New entry in the ChangeLog.md added.
• No warning raised in Debug mode.
• All continuous integration tests pass (Github Actions)

[kerautret]

Thanks @Seangongx just a typo and could you please add an entry on the changelog file that probably forget to add ?

[kerautret]

Fine for me thanks @Seangongx