Deps: Remove androidx legacy dependency from wordpress comments

This dependency is completely unused.

FYI: It got introduced as part of this
(ad68cc9) commit, a part of the
AndroidX migration.

------------------------------------------------------------------------

This removal was suggested by the dependency analysis report, see below:

Advice for :wordpress-comments
Unused dependencies which should be removed:
  implementation 'androidx.legacy:legacy-support-v4:1.0.0'

Author: ParaskP7

wordpress-comments/build.gradle

@@ -38,7 +38,6 @@ android {
 dependencies {
     implementation aztecProjectDependency
 
-    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
     implementation 'com.google.android.material:material:1.0.0'
     implementation "org.wordpress:utils:$wordpressUtilsVersion"