Use sp units for text sizes where they don't break layout

mastodon/src/main/res/layout/fragment_compose.xml

@@ -28,6 +28,7 @@
 				android:background="@drawable/bg_cw_edit"
 				android:padding="16dp"
 				android:minHeight="56dp"
+				android:textSize="16sp"
 				tools:visibility="visible"/>
 
 			<TextView
@@ -96,6 +97,7 @@
 					android:paddingRight="16dp"
 					android:paddingBottom="16dp"
 					android:textAppearance="@style/m3_body_large"
+					android:textSize="16sp"
 					android:gravity="top"
 					android:background="@null"
 					android:hint="@string/compose_hint"