perf: move up external url check before fs path checks

[suguanYang]

Description

The real problem:
I was developing a plugin that can distribute the optimizied dependencies, so the resolved id will like this: https://xxx/react@18.2.0/jsx-runtime, for vite perspective, the optimized dependencies should all local files, the resolved id will become something like this /@fs/https:/xxx/react@18.2.0/jsx-runtime?v=628f3470

I can not ask vite community to consider my use case, but I think we could optimize this code since there is no meaning that we put the external condition after some file related conditions.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[suguanYang]

@sapphi-red Hi, can you help tp review this?

[suguanYang]

@yyx990803 Hi Evan, can you have a look at this?

[suguanYang]

@bluwy Hi bluwy, thanks for your review and comments, I have made some changes that do not affect the url variable, and this has less impact than the previous one.