fix(react-router-dev): avoid duplicate stylesheet links for nested suspended routes

[joseph0926]

This seems to be a problem caused by adding #, similar to the previously submitted PR (#14687), so I attempted to fix it.

Description

This PR fixes duplicated stylesheet links in Framework mode for suspended components in nested routes

When reproducing the issue, I confirmed it does not occur in dev mode, but does occur when running the built app.
The behavior appears related to the forced-unique # stylesheet href logic introduced to preserve dynamic-import CSS behavior.

Changes

• Added e2e test
  • integration/vite-css-suspended-duplicate-test.ts
• Updated Vite plugin stylesheet href handling
  • packages/react-router-dev/vite/plugin.ts

Fixes #14754

[changeset-bot]

🦋 Changeset detected

Latest commit: 200ba23

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

This PR includes changesets to release 11 packages

Name	Type
@react-router/dev	Patch
@react-router/fs-routes	Patch
@react-router/remix-routes-option-adapter	Patch
create-react-router	Patch
react-router	Patch
react-router-dom	Patch
@react-router/architect	Patch
@react-router/cloudflare	Patch
@react-router/express	Patch
@react-router/node	Patch
@react-router/serve	Patch

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