Address Copilot review comments

- query-ctor-maxAwaitTimeMS-001: remove UINT32_MAX case (4294967295
  overflows PHP_INT_MAX on 32-bit platforms, causing float coercion)
- session-getServer-001: update comment to accurately reflect that
  mongos pinning was removed in MongoDB 6.0+

Author: GromNaN

tests/query/query-ctor-maxAwaitTimeMS-001.phpt

@@ -9,14 +9,10 @@ echo "maxAwaitTimeMS=0: OK\n";
 $q = new MongoDB\Driver\Query([], ['maxAwaitTimeMS' => 1000]);
 echo "maxAwaitTimeMS=1000: OK\n";
 
-$q = new MongoDB\Driver\Query([], ['maxAwaitTimeMS' => 4294967295]);
-echo "maxAwaitTimeMS=4294967295: OK\n";
-
 ?>
 ===DONE===
 <?php exit(0); ?>
 --EXPECT--
 maxAwaitTimeMS=0: OK
 maxAwaitTimeMS=1000: OK
-maxAwaitTimeMS=4294967295: OK
 ===DONE===

tests/session/session-getServer-001.phpt

@@ -11,8 +11,8 @@ require_once __DIR__ . "/../utils/basic.inc";
 $manager = create_test_manager();
 $session = $manager->startSession();
 
-/* Session is not pinned to a server until a transaction operation is executed
- * on a sharded cluster. Returns null when the session is not pinned. */
+/* Session::getServer() returns null, as sessions are not pinned to a server.
+ * Note: mongos pinning for sharded transactions was removed in MongoDB 6.0. */
 var_dump($session->getServer());
 
 ?>