Prepare for fix to flutter/flutter#109339. (Baseflow#102)

Currently, in some circumstances where a subclasses of `PlatformInterface` erroneously uses `implements` rather than `extends`, a `NoSuchMethodError` will be thrown (in spite of the documentation at https://pub.dev/documentation/plugin_platform_interface/latest/plugin_platform_interface/PlatformInterface/verify.html claiming that `AssertionError` will be thrown). After flutter/flutter#109339 is fixed, the correct type of exception will be thrown. To avoid a test breakage in `geocoding_platform_interface_test.dart` when the fix happens, we need to modify the test so that it doesn't care what kind of exception is thrown.

Author: stereotype441

geocoding_platform_interface/test/geocoding_platform_interface_test.dart

@@ -19,7 +19,14 @@ void main() {
  test('Cannot be implemented with `implements`', () {
  expect(() {
  GeocodingPlatform.instance = ImplementsGeocodingPlatform();
- }, throwsNoSuchMethodError);
+ // In versions of `package:plugin_platform_interface` prior to fixing
+ // https://github.com/flutter/flutter/issues/109339, an attempt to
+ // implement a platform interface using `implements` would sometimes
+ // throw a `NoSuchMethodError` and other times throw an
+ // `AssertionError`. After the issue is fixed, an `AssertionError` will
+ // always be thrown. For the purpose of this test, we don't really care
+ // what exception is thrown, so just allow any exception.
+ }, throwsA(anything));
  });
 
  test('Can be extended', () {