feat(remix)!: Drop support for Remix v1 (#14988)

- Drops support for Remix v1.
- Drops support for React <18 in Remix (Remix v2 depends on React 18)
- Removes v1 integration tests
- Removes v1 e2e tests

ref ##14263

---------

Co-authored-by: Onur Temizkan <onur@narval.co.uk>

Author: chargome

.github/workflows/build.yml

@@ -756,7 +756,6 @@ jobs:
       fail-fast: false
       matrix:
         node: [18, 20, 22]
-        remix: [1, 2]
     steps:
       - name: Check out current commit (${{ needs.job_get_metadata.outputs.commit_label }})
         uses: actions/checkout@v4
@@ -779,7 +778,6 @@ jobs:
       - name: Run integration tests
         env:
           NODE_VERSION: ${{ matrix.node }}
-          REMIX_VERSION: ${{ matrix.remix }}
         run: |
           cd packages/remix
           yarn test:integration:ci