ENH: add width, height, and data_size properties to ImageFile

[itisar-345]

Previously, inspecting an image's dimensions or size required fully decoding it via .image or .data, even if the caller only wanted to
filter out images that are too large to process.

ImageFile now exposes:

• .width : image width in pixels, read from the stream's /Width
• .height : image height in pixels, read from the stream's /Height
• .data_size : compressed byte size of the stream, read from the raw stream bytes (no decompression)

All three are read directly from the PDF stream header/raw bytes and require no image decoding, so they remain cheap even for large or numerous images.

.data and .image continue to be populated eagerly as before; this change is purely additive and does not alter existing behavior.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.87%. Comparing base (efc511b) to head (d7a5808).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3881   +/-   ##
=======================================
  Coverage   97.86%   97.87%           
=======================================
  Files          57       57           
  Lines       10738    10761   +23     
  Branches     2006     2011    +5     
=======================================
+ Hits        10509    10532   +23     
  Misses        127      127           
  Partials      102      102           

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[stefan6419846]

Thanks for the PR. I have added some remarks to the proposed changes.