Rename "onPositiveClicked" and "onNegativeClicked"

These functions have been renamed to "onGutenbergDialogPositiveClicked" and "onGutenbergDialogNegativeClicked" respectively, in order to make their purpose clearer.

libs/editor/WordPressEditor/src/main/java/org/wordpress/android/editor/gutenberg/GutenbergDialogFragment.kt

@@ -19,11 +19,11 @@ class GutenbergDialogFragment() : AppCompatDialogFragment() {
     private var dismissedByNegativeButton = false
 
     interface GutenbergDialogPositiveClickInterface {
-        fun onPositiveClicked(instanceTag: String, mediaId: Int)
+        fun onGutenbergDialogPositiveClicked(instanceTag: String, mediaId: Int)
     }
 
     interface GutenbergDialogNegativeClickInterface {
-        fun onNegativeClicked(instanceTag: String)
+        fun onGutenbergDialogNegativeClicked(instanceTag: String)
     }
 
     interface GutenbergDialogOnDismissByOutsideTouchInterface {
@@ -85,7 +85,7 @@ class GutenbergDialogFragment() : AppCompatDialogFragment() {
                 dismissedByPositiveButton = true
                 val parentFragment: Fragment? = parentFragment
                 if (parentFragment != null) {
-                        (parentFragment as GutenbergDialogPositiveClickInterface).onPositiveClicked(mTag, mMediaId)
+                        (parentFragment as GutenbergDialogPositiveClickInterface).onGutenbergDialogPositiveClicked(mTag, mMediaId)
                 }
             }.setCancelable(true)
         }
@@ -95,7 +95,7 @@ class GutenbergDialogFragment() : AppCompatDialogFragment() {
                 dismissedByNegativeButton = true
                 val parentFragment: Fragment? = parentFragment
                 if (parentFragment != null) {
-                        (parentFragment as GutenbergDialogNegativeClickInterface).onNegativeClicked(mTag)
+                        (parentFragment as GutenbergDialogNegativeClickInterface).onGutenbergDialogNegativeClicked(mTag)
                 }
             }
         }

libs/editor/WordPressEditor/src/main/java/org/wordpress/android/editor/gutenberg/GutenbergEditorFragment.java

@@ -1381,7 +1381,7 @@ public void showNotice(String message) {
     }
 
     @Override
-    public void onPositiveClicked(@NotNull String instanceTag, int mediaId) {
+    public void onGutenbergDialogPositiveClicked(@NotNull String instanceTag, int mediaId) {
         switch (instanceTag) {
             case TAG_REPLACE_FEATURED_DIALOG:
                 setFeaturedImage(mediaId);
@@ -1390,7 +1390,7 @@ public void onPositiveClicked(@NotNull String instanceTag, int mediaId) {
     }
 
     @Override
-    public void onNegativeClicked(@NotNull String instanceTag) {
+    public void onGutenbergDialogNegativeClicked(@NotNull String instanceTag) {
         switch (instanceTag) {
             case TAG_REPLACE_FEATURED_DIALOG:
                 // Dismiss dialog with no action.