fix send button assets

Closes #2757

// FREEBIE

res/layout/conversation_activity.xml

@@ -105,7 +105,7 @@
                     android:contentDescription="@string/conversation_activity__send"
                     android:nextFocusLeft="@+id/embedded_text_editor"
                     android:padding="12dp"
-                    android:src="?conversation_send_button_sms_insecure"
+                    android:src="?conversation_transport_sms_indicator"
                     android:focusable="true"
                     android:clickable="false"
                     android:enabled="false" />

res/values/attrs.xml

@@ -27,9 +27,6 @@
     <attr name="conversation_background" format="reference|color"/>
     <attr name="conversation_editor_background" format="reference"/>
     <attr name="conversation_editor_text_color" format="reference|color"/>
-    <attr name="conversation_send_button_push" format="reference"/>
-    <attr name="conversation_send_button_sms_secure" format="reference"/>
-    <attr name="conversation_send_button_sms_insecure" format="reference"/>
     <attr name="conversation_delivery_delivered" format="reference"/>
     <attr name="conversation_transport_sms_indicator" format="reference"/>
     <attr name="conversation_transport_push_indicator" format="reference"/>

res/values/themes.xml

@@ -44,11 +44,8 @@
         <item name="conversation_background">#ffffffff</item>
         <item name="conversation_editor_background">@drawable/textlines</item>
         <item name="conversation_editor_text_color">#ff111111</item>
-        <item name="conversation_send_button_push">@drawable/ic_send_push</item>
-        <item name="conversation_send_button_sms_secure">@drawable/ic_send_sms_secure</item>
-        <item name="conversation_send_button_sms_insecure">@drawable/ic_send_sms_insecure</item>
         <item name="conversation_delivery_delivered">@drawable/ic_delivery_delivered_dark</item>
-        <item name="conversation_transport_sms_indicator">@drawable/ic_send_sms_insecure_dark</item>
+        <item name="conversation_transport_sms_indicator">@drawable/ic_send_sms_insecure</item>
         <item name="conversation_transport_push_indicator">@drawable/ic_send_push</item>
         <item name="conversation_transport_popup_background">@color/white</item>
         <item name="conversation_emoji_toggle">@drawable/ic_emoji_dark</item>
@@ -176,9 +173,6 @@
         <item name="conversation_background">@color/black</item>
         <item name="conversation_editor_background">@drawable/textlines_dark</item>
         <item name="conversation_editor_text_color">#ffeeeeee</item>
-        <item name="conversation_send_button_push">@drawable/ic_send_push</item>
-        <item name="conversation_send_button_sms_secure">@drawable/ic_send_sms_secure</item>
-        <item name="conversation_send_button_sms_insecure">@drawable/ic_send_sms_insecure_dark</item>
         <item name="conversation_delivery_delivered">@drawable/ic_delivery_delivered_dark</item>
         <item name="conversation_transport_sms_indicator">@drawable/ic_send_sms_insecure_dark</item>
         <item name="conversation_transport_push_indicator">@drawable/ic_send_push</item>