fix(i18n): parse params and props correctly with fallback

[mtwilliams-code]

Changes

This modifies the logic in getParams and getProps slightly to handle i18n fallback edge cases.

1. If there are no static path matches in getProps, we return early to avoid an error that occurs in the findPathItemByKey call. This should be a nonbreaking change - I dont see any side effects from these calls and it returns an empty object anyway if there are no static paths. I'm not entirely sure I understand the intended behavior in all scenarios here, so feel free to correct.

2. In getParams If there are no param matches from route.pattern, we also try the patterns from route.fallbackRoutes so that we correctly parse out the param from the localized URL.

Fixes #12701

Testing

Change to the i18n-routing-fallback fixture to allow testing SSR params and a new test added for Fallback rewrite SSR to validate the param is received correctly. Before this change this test will crash with

12:56:12 [ERROR] TypeError: Missing parameter: id
    at getParameter (file:///Users/mtwilliams/Codebase/astro/packages/astro/test/fixtures/i18n-routing-fallback/dist/i18n-routing-fallback/server/manifest_CSai1Xy5.mjs:24:13)
    ...
    
    500 !== 200
    
        at TestContext.<anonymous> (file:///Users/mtwilliams/Codebase/astro/packages/astro/test/i18n-routing.test.js:2094:10)
        at async Test.run (node:internal/test_runner/test:574:9)
        at async Suite.processPendingSubtests (node:internal/test_runner/test:318:7) {
      generatedMessage: true,
      code: 'ERR_ASSERTION',
      actual: 500,
      expected: 200,
      operator: 'strictEqual'
    }

Docs

This fixes a bug and restores intended behavior, so no docs necessary.

[changeset-bot]

🦋 Changeset detected

Latest commit: de2584d

The changes in this PR will be included in the next version bump.

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[codspeed-hq]

CodSpeed Performance Report

Merging #12709 will not alter performance

_{Comparing mtwilliams-code:fix-i18n-params (de2584d) with main (e3bfd93)}

Summary

✅ 4 untouched benchmarks

[mtwilliams-code]

LMK if this is too many tests

[ematipico]

This was an amazing fix, thank you @mtwilliams-code for that!