Fix incorrect PDF title display when multiple language titles present in XMP metadata (issue 20801)

[nyxsky404]

Fixes #20801

Problem

When a PDF has multiple language titles in XMP metadata using rdf:Alt, the titles were being concatenated instead of selecting a single title. For example, a PDF with both x-default and en language titles would display "Hello WorldHello World" instead of "Hello World".

Solution

• Added _parseLangAlt method to properly handle rdf:Alt elements for dc:title and dc:description
• Selects x-default language entry if present, otherwise uses the first entry
• Falls back to textContent for backward compatibility with plain text values
• Enabled hasAttributes option in SimpleXMLParser to read xml:lang attributes

Testing

• Added unit tests for multiple language titles with x-default
• Added unit tests for multiple language descriptions without x-default
• All existing metadata tests continue to pass

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.56%. Comparing base (3127492) to head (7443fab).
⚠️ Report is 110 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #20874      +/-   ##
==========================================
+ Coverage   62.51%   62.56%   +0.04%     
==========================================
  Files         173      173              
  Lines      121246   121278      +32     
==========================================
+ Hits        75796    75872      +76     
+ Misses      45450    45406      -44     

Flag	Coverage Δ
fonttest	7.66% <ø> (?)
unittestcli	62.53% <100.00%> (+0.01%)	⬆️

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