[v3.8.5] Make dispatchImmediately variable be a const value which will help treeshaking.

[dumganhar]

Re: #17715

Changelog

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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.

[dumganhar]

@cocos-robot run test cases

[github-actions]

👍 Package size ⤵ -700 bytes, old: 5376730, new: 5376030

Interface Check Report

This pull request does not change any public interfaces !

[github-actions]

@dumganhar, Please check the result of run test cases:

• Test Platform: PR-Test
• Editor Version: v3.8.5
• Task Result: FAIL
• Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/f0392359-edf9-460a-acc8-ee0cdca12399/-1
• GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/11819336332

Task Details

Platform	build	boot	runned	crashScene	FailScene
web-mobile	PASS	PASS	FAIL		shield-node
ios	PASS	PASS	FAIL		shield-node
mac	PASS	PASS	FAIL		shield-node

[github-actions]

@dumganhar, Please check the result of run test cases:

• Test Platform: PR-Test
• Editor Version: v3.8.5
• Task Result: FAIL
• Task URL: https://cctest.cocos.org/#/reportview/PR-TEST/9390ddcf-952e-4463-8fa0-ebd38c83f732/-1
• GitHub Action: https://github.com/cocos/cocos-engine/actions/runs/11819336332

Task Details

Platform	build	boot	runned	crashScene	FailScene
windows	PASS	PASS	FAIL		shield-node