chore: fix Connection type (#517)

The external `Connection` type regressed in
https://github.com/microsoft/playwright-mcp/pull/490/files#diff-a6be0583428e46844273df76939f02077073da3075716fc57d291a5f2463eaf5,
where the `connect()` function was removed but not from the types. I've
changed the code so we import from there, similar to how we do it for
`config.d.ts`, so this shouldn't happen again.

src/index.ts

@@ -14,7 +14,8 @@
  * limitations under the License.
  */
 
-import { Connection, createConnection as createConnectionImpl } from './connection.js';
+import { createConnection as createConnectionImpl } from './connection.js';
+import type { Connection } from '../index.js';
 import { resolveConfig } from './config.js';
 import { contextFactory } from './browserContextFactory.js';