enforce StreamReadConstraints.maxNestingDepth in FromXmlParser

[Sahana2524]

FromXmlParser increments read-context nesting depth on each child Object/Array, but never validates it, so a configured StreamReadConstraints.maxNestingDepth is ignored when reading XML.

• ToXmlGenerator already validates StreamWriteConstraints.maxNestingDepth on the write side, and jackson-core JsonParserBase does the same on read, so the XML read path was the outlier
• the default limit (500) sits below Woodstox element-depth default (1000), so three existing deep-nesting tests reached the jackson-core limit first; I raised their maxNestingDepth so each still exercises the limit it was written for (Woodstox element depth, token count)

New test covers rejection past a low configured limit while staying within the Stax element-depth limit.

[github-actions]

🧪 Code Coverage Report

Metric	Coverage	Change
Instructions	73.70%	📉 -0.010%
Branches	68.56%	📈 +0.000%

Coverage data generated from JaCoCo test results