Fix #599: handle skipping of CBOR string refs

[cowtowncoder]

Summary

Problem:

When using CBOR with string references enabled, deserialization failed if a string value was skipped (e.g., when a property is ignored via @JsonIgnoreProperties). The parser would skip over the string without adding it to the string reference table, causing later string references to fail with "String reference out of range" errors.

Root Cause:

The _skipIncomplete() method in CBORParser was designed to skip over string/bytes content without actually reading it. However, when in a stringref namespace, the parser needs to read and potentially store these values in the reference table for later use.

Solution:

Modified _skipIncomplete() in CBORParser.java (lines 3418-3432) to:

1. Check if we're in a stringref namespace (!_stringRefs.empty())
2. If yes, actually read the value using the appropriate finish methods (_finishTextToken() for text, _finishBytes() for bytes)
3. The finish methods already contain logic to determine if values should be added to the reference table based on shouldReferenceString()
4. If not in a stringref namespace, use the original skip logic