center icon in small send button (#4875)

2 users complained already 😔 

Before:

![before](https://github.com/user-attachments/assets/d3472856-a01e-42c6-b477-88fc376c63de)

After:

![after](https://github.com/user-attachments/assets/6722dac7-59d3-47b7-9718-6caae5eb0bec)

app/src/main/java/com/keylesspalace/tusky/components/compose/view/TootButton.kt

@@ -38,9 +38,9 @@ class TootButton
     init {
         if (smallStyle) {
             setIconResource(R.drawable.ic_send_24dp)
+            iconPadding = 0
         } else {
             setText(R.string.action_send)
-            iconGravity = ICON_GRAVITY_TEXT_START
         }
         val padding = resources.getDimensionPixelSize(R.dimen.toot_button_horizontal_padding)
         setPadding(padding, 0, padding, 0)

app/src/main/res/layout/activity_compose.xml

@@ -378,7 +378,8 @@
             android:layout_width="@dimen/toot_button_width"
             android:layout_height="wrap_content"
             android:layout_marginStart="10dp"
-            android:textSize="?attr/status_text_medium" />
+            android:textSize="?attr/status_text_medium"
+            app:iconGravity="textStart" />
 
     </LinearLayout>