Fixed use labelShadow not setting contentSize correctly

[haiyoucuv]

Re: # Fixed use labelShadow not setting contentSize correctly

Changelog

• cocos/2d/assembler/label/text-processing.ts

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Continuous Integration

This pull request:

• needs automatic test cases check.

  Manual trigger with @cocos-robot run test cases afterward.

• does not change any runtime related code or build configuration

  If any reviewer thinks the CI checks are needed, please uncheck this option, then close and reopen the issue.

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Compatibility Check

This pull request:

• changes public API, and have ensured backward compatibility with deprecated features.
• affects platform compatibility, e.g. system version, browser version, platform sdk version, platform toolchain, language version, hardware compatibility etc.
• affects file structure of the build package or build configuration which requires user project upgrade.
• introduces breaking changes, please list all changes, affected features and the scope of violation.

[haiyoucuv]

Fixed use labelShadow not setting contentSize correctly
修复了使用labelShadow后contentSize没有设置到正确的值导致文字显示变形的问题

Before(修复前):

After(修复后):

Before with large value(修复前，使用极端值):

After with large value(修复后，使用极端值):

[github-actions]

👍 Package size ⤵ -24 bytes, old: 5195606, new: 5195582

Interface Check Report

This pull request does not change any public interfaces !