[v3.8.6] Fix a mangleProperties issue which is caused by using as any in trail.ts.

[dumganhar]

Re: #

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.

[github-actions]

⚠️ Package size ⤴ 9 bytes, old: 5233060, new: 5233069

Interface Check Report

! WARNING this pull request has changed these public interfaces:

@@ -68192,9 +68192,9 @@
             clear(): void;
             getModel(): _cocos_particle_models_particle_batch_model__default | null;
             protected _initModel(): void;
             updateTrailMaterial(): void;
-            getDefaultTrailMaterial(): null;
+            getDefaultTrailMaterial(): Material | null;
             abstract getParticleCount(): number;
             abstract getFreeParticle(): _cocos_particle_particle__Particle | null;
             abstract onMaterialModified(index: number, material: Material): void;
             abstract onRebuildPSO(index: number, material: Material): void;

[dumganhar]

@minggo, I merged this PR since daily build depends on this.
If you get something to comment, I will update the code later.