fix: Incorrect assertion

[tattn]

Description

smartBannerLandscape is called on iOS only:

googleads-mobile-flutter/packages/google_mobile_ads/lib/src/ad_containers.dart

Lines 189 to 192 in e48b29a

	} else if (defaultTargetPlatform == TargetPlatform.iOS &&
	orientation == Orientation.landscape) {
	return smartBannerLandscape;
	}

But the assertion is android. So the following error always occurs when the orientation is landscape on iOS.

======== Exception caught by widgets library =======================================================
The following assertion was thrown while rebuilding dirty elements:
'package:google_mobile_ads/src/ad_containers.dart': Failed assertion: line 214 pos 12: 'defaultTargetPlatform == TargetPlatform.android': is not true.

Related Issues

No issue.

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