remove io import for web

0/0 points: WASM compatibility
Package not compatible with runtime wasm
Because:

package:maplibre/maplibre.dart that imports:
package:maplibre/src/map.dart that imports:
package:maplibre/src/platform_interface.dart that imports:
package:maplibre/src/native/platform_native.dart that imports:
package:maplibre/src/native/widget_state.dart that imports:
dart:io
This package is not compatible with runtime wasm, and will not be rewarded full points in a future version of the scoring model.

See https://dart.dev/web/wasm for details.

lib/src/platform_interface.dart

@@ -1,6 +1,5 @@
 import 'package:flutter/widgets.dart';
 import 'package:maplibre/maplibre.dart';
-import 'package:maplibre/src/native/platform_native.dart';
 
 /// https://pub.dev/packages/plugin_platform_interface#a-note-about-base
 abstract base class PlatformInterface {
@@ -9,7 +8,6 @@ abstract base class PlatformInterface {
 
   /// The default instance of [PlatformInterface] to use.
   ///
-  /// Defaults to [PlatformNative].
   /// Platform-specific implementations should set this with their own
   /// platform-specific class that extends [PlatformInterface] when
   /// they register themselves.