Skip malformed JSON object after a parse error

[Develop-KIM]

JacksonJsonObjectReader.read() rethrows a JacksonException as a ParseException, but it leaves the parser cursor inside the malformed object. The next read() then finds a token other than START_OBJECT and returns null, which the caller takes as the end of the input, so the step stops early while valid items are still there. That makes it impossible to skip a ParseException.

With this input the first item reads fine and the second throws ParseException as expected, but the third comes back null instead of CCC:

[
  {"isin":"AAA","quantity":1,"price":1.0,"customer":"foo"},
  {"isin":"BBB","quantity":"not a number","price":2.0,"customer":"bar"},
  {"isin":"CCC","quantity":3,"price":3.0,"customer":"baz"}
]

This skips to the end of the malformed object before rethrowing, so the remaining items stay readable. It tracks the nesting depth rather than looking for the next END_OBJECT, so an item containing nested objects is drained correctly too.

GsonJsonObjectReader reads through a JsonReader and I didn't touch it here — happy to look at it separately if it has the same gap.

Resolves #4701

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Written with AI assistance (Claude); I reviewed the change and verified it myself. JacksonJsonObjectReaderTests fails on current main (the first two cases) and passes with the fix, and the item.json package suite plus spring-javaformat:validate are green.