teams/cloud/wsl: Use native "wsl" image type

This introduces extra validation for WSL image creation to ensure
the result is usable.

teams/cloud/wsl.xml

@@ -3,7 +3,7 @@
 		<profile name="WSL-Base" description="Windows Subsystem for Linux Base"/>
 	</profiles>
 	<preferences profiles="WSL-Base">
-		<type image="tbz"/>
+		<type image="wsl"/>
 		<timezone>Etc/UTC</timezone>
 		<locale>en_US</locale>
 		<rpm-locale-filtering>false</rpm-locale-filtering>

tmt/plans/wsl/build.fmf

@@ -2,7 +2,7 @@ summary: Build the Windows Subsystem for Linux image
 discover:
     how: fmf
 environment:
-    image_type: tbz
+    image_type: wsl
     image_profile: WSL-Base
     kiwi_file: Fedora.kiwi
 execute: