Revert "Support React 18 in Pages Router"

[timneutkens]

Reverts #69484

[ijjk]

Failing test suites

Commit: a41b4e5

pnpm test-start test/e2e/app-dir/rsc-basic/rsc-basic.test.ts

• app dir - rsc basics > should be able to navigate between rsc routes

Expand output

● app dir - rsc basics › should be able to navigate between rsc routes

request.allHeaders: Target page, context or browser has been closed

  168 |         page.on('request', (request) => {
  169 |           requestsCount++
> 170 |           return request.allHeaders().then((headers) => {
      |                          ^
  171 |             if (
  172 |               headers['RSC'.toLowerCase()] === '1' &&
  173 |               // Prefetches also include `RSC`

  at Page.allHeaders (e2e/app-dir/rsc-basic/rsc-basic.test.ts:170:26)

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