Fix TS6 baseUrl deprecation for extended tsconfig (#91855)
## Summary
- handle `compilerOptions.baseUrl` inherited via `extends` in TS6 config
normalization
- rewrite `paths` using the resolved base URL and remove `baseUrl` from
parsed compiler options
- keep existing behavior for direct `baseUrl` while avoiding TS5101 in
typecheck
follow-up to https://github.com/vercel/next.js/pull/91847
## Validation
- `IS_WEBPACK_TEST=1 NEXT_TEST_MODE=start NEXT_TEST_REACT_VERSION=18.3.1
__NEXT_EXPERIMENTAL_STRICT_ROUTE_TYPES=true pnpm testheadless
test/e2e/app-dir/next-config-ts/tsconfig-extends/next-config-ts-tsconfig-extends-esm.test.ts`
- `IS_WEBPACK_TEST=1 NEXT_TEST_MODE=start NEXT_TEST_REACT_VERSION=18.3.1
__NEXT_EXPERIMENTAL_STRICT_ROUTE_TYPES=true pnpm testheadless
test/e2e/app-dir/next-config-ts/import-alias-paths-with-baseurl/next-config-ts-import-alias-paths-with-baseurl-esm.test.ts`
