Fix the license text bundled for pdf.js.qcms

[calixteman]

The file external/qcms/LICENSE_PDFJS_QCMS contained a BSD-2-Clause text (copied from the openjpeg one), whereas https://github.com/mozilla/pdf.js.qcms is released under the MIT license.

It fixes #21745.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.08%. Comparing base (7364bca) to head (79ccf81).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #21747      +/-   ##
==========================================
- Coverage   90.09%   90.08%   -0.01%     
==========================================
  Files         264      264              
  Lines       67234    67234              
==========================================
- Hits        60574    60568       -6     
- Misses       6660     6666       +6     

Flag	Coverage Δ
browsertest	66.34% <ø> (-0.01%)	⬇️
fonttest	8.99% <ø> (ø)
integrationtest	69.28% <ø> (-0.02%)	⬇️
unittest	58.23% <ø> (+0.01%)	⬆️
unittestcli	56.58% <ø> (-0.02%)	⬇️

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