remove ktx libraries (#7106)

This PR removes all the KTX libraries and the docs associated with them.
KTX libraries were deprecated a long time ago and now we are removing
these as a part of our breaking change release.

---------

Co-authored-by: Rodrigo Lazo Paz <[email protected]>
Co-authored-by: Rodrigo Lazo <[email protected]>

Author: VinayGuthal

appcheck/firebase-appcheck-playintegrity/firebase-appcheck-playintegrity.gradle

@@ -52,7 +52,6 @@ dependencies {
     api project(':appcheck:firebase-appcheck')
     api 'com.google.firebase:firebase-annotations:16.2.0'
     api 'com.google.firebase:firebase-common:21.0.0'
-    api 'com.google.firebase:firebase-common-ktx:21.0.0'
     api 'com.google.firebase:firebase-components:18.0.0'
 
     implementation libs.playservices.base

appcheck/firebase-appcheck/api.txt

@@ -41,14 +41,3 @@ package com.google.firebase.appcheck {
 
 }
 
-package com.google.firebase.appcheck.ktx {
-
-  public final class FirebaseAppCheckKt {
-    method @Deprecated public static com.google.firebase.appcheck.FirebaseAppCheck appCheck(com.google.firebase.ktx.Firebase, com.google.firebase.FirebaseApp app);
-    method @Deprecated public static operator String component1(com.google.firebase.appcheck.AppCheckToken);
-    method @Deprecated public static operator long component2(com.google.firebase.appcheck.AppCheckToken);
-    method @Deprecated public static com.google.firebase.appcheck.FirebaseAppCheck getAppCheck(com.google.firebase.ktx.Firebase);
-  }
-
-}
-