Use unsigned element count when parsing EscherArrayProperty

[jmestwa-coder]

Summary

Use an unsigned element count when parsing EscherArrayProperty.

Changes

• Replace LittleEndian.getShort() with LittleEndian.getUShort() when reading the array element count (nElems) in EscherArrayProperty#setArrayData.
• Align parsing behavior with the existing unsigned accessors in the same class.
• Ensure values in the full unsigned range (0-65535) are interpreted correctly.

Why

• The element count field is treated as unsigned elsewhere in EscherArrayProperty.
• Reading the field as a signed value can misinterpret counts greater than 32767.
• This creates inconsistent behavior between parsing and subsequent access to the property data.

Tests

• Added a regression test covering an element count larger than 32767.
• Verified that the parsed complex data size is calculated correctly using the unsigned value.

[pjfanning]

lgtm