Deps: Update gutenberg kit version to trunk hash

This 'Gutenberg Kit' trunk hash updates the library to that branch
version where 'Gradle & AGP' is also upgraded to version
'8.12.1 & 8.8.1' respectively.

Gutenberg Kit PR: https://github.com/wordpress-mobile/
GutenbergKit/pull/92

This step is required in order to check that these 'Gutenberg Kit'
related changes work as expected for JP/WPAndroid.

gradle/libs.versions.toml

@@ -72,7 +72,7 @@ google-play-services-auth = '20.4.1'
 google-services = '4.4.2'
 gravatar = '2.3.1'
 greenrobot-eventbus = '3.3.1'
-gutenberg-kit = '92-dcf21d75ebf679c020b3d6f0c9fe80694884a234'
+gutenberg-kit = 'trunk-c7efee1859bacda21537ba144ac55c8abe4eaec8'
 gutenberg-mobile = 'v1.121.0'
 indexos-media-for-mobile = '43a9026f0973a2f0a74fa813132f6a16f7499c3a'
 jackson-databind = '2.12.7.1'