fix: proxy html path should be encoded

[patak-dev]

Description

After #13581, the htmlProxy URLs were unencoded. This PR reverts this change, still fixing the linked bugs (there was a test added in that PR).

I tried two approaches, the second commit has the keys in the proxy HTML cache decoded. I think this is the simpler of the two.

There was also an issue when pre-transforming requests in index HTML middleware, the URLs sent to warmupRequest should be decoded. Once I did the fix, the ssr-deps playground started to fail for this reason. I added the decoding logic there too.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

[patak-dev]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI on 4ea1c57: Open

suite	result	latest scheduled
analogjs	✅ success	✅ success
astro	✅ success	✅ success
histoire	✅ success	❌ failure
ladle	✅ success	✅ success
laravel	❌ failure	❌ failure
marko	✅ success	✅ success
nuxt	❌ failure	❌ failure
nx	✅ success	✅ success
previewjs	✅ success	✅ success
qwik	✅ success	✅ success
rakkas	✅ success	✅ success
sveltekit	✅ success	❌ failure
unocss	✅ success	✅ success
vike	✅ success	✅ success
vite-plugin-pwa	✅ success	✅ success
vite-plugin-react	✅ success	✅ success
vite-plugin-react-pages	✅ success	✅ success
vite-plugin-react-swc	✅ success	✅ success
vite-plugin-svelte	✅ success	✅ success
vite-plugin-vue	✅ success	✅ success
vite-setup-catalogue	✅ success	✅ success
vitepress	✅ success	✅ success
vitest	✅ success	✅ success