fix: 修复非官方引擎在 build 时版本号被错误覆盖的问题

[boomwwww]

添加了对于type字段的判断以解决问题

[gemini-code-assist]

Code Review

This pull request modifies the engine version update script to use webgalVersion for version tracking and introduces a conditional check to update the version field only for 'official' engine types. A review comment suggests adding a fallback for the oldVersion variable to prevent it from being undefined if the webgalVersion property is missing in the source file.

[gemini-code-assist]

oldVersion 现在被赋值为 engineJson.webgalVersion。如果该字段在 engine.json 中不存在（例如在旧版本的引擎中），oldVersion 将会是 undefined。这可能会导致后续的日志输出不够清晰。建议增加回退到 engineJson.version 的逻辑。

Suggested change

	const oldVersion = engineJson.webgalVersion;
	const oldVersion = engineJson.webgalVersion || engineJson.version;