Fix ktx2 offset is not correct

[gz65555]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

[codecov]

Codecov Report

Attention: 6 lines in your changes are missing coverage. Please review.

Comparison is base (014de1d) 64.28% compared to head (3a91f1c) 65.02%.
Report is 1 commits behind head on main.

❗ Current head 3a91f1c differs from pull request most recent head 4c0d198. Consider uploading reports for the commit 4c0d198 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1820      +/-   ##
==========================================
+ Coverage   64.28%   65.02%   +0.73%     
==========================================
  Files         473      473              
  Lines       23757    23750       -7     
  Branches     3369     3368       -1     
==========================================
+ Hits        15273    15444     +171     
+ Misses       7294     7107     -187     
- Partials     1190     1199       +9     

Files	Coverage Δ
packages/core/src/Engine.ts	87.04% <ø> (-0.13%)	⬇️
packages/core/src/asset/ResourceManager.ts	60.09% <100.00%> (ø)
packages/loader/src/ktx2/KTX2Container.ts	6.89% <0.00%> (ø)
...resource-deserialize/resources/mesh/MeshDecoder.ts	2.19% <0.00%> (ø)
packages/loader/src/ktx2/KTX2Loader.ts	14.77% <33.33%> (+1.72%)	⬆️

... and 19 files with indirect coverage changes

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[GuoLei1990]

KTX2 Texture Usage.