Don't parse content of inline images

[PrinsFrank]

Fixes #475

[codecov-commenter]

Codecov Report

❌ Patch coverage is 57.14286% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 51.96%. Comparing base (63368fc) to head (0bad563).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/Document/ContentStream/ContentStreamParser.php	57.14%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #476      +/-   ##
============================================
- Coverage     51.97%   51.96%   -0.02%     
- Complexity     1890     1897       +7     
============================================
  Files           108      108              
  Lines          3563     3568       +5     
============================================
+ Hits           1852     1854       +2     
- Misses         1711     1714       +3     

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