Fix text color of search in top bar (Z#23208359)

Author: robbi5

pretixscan/app/src/main/res/values/styles.xml

@@ -69,5 +69,6 @@
         <item name="colorOnSurface">@color/white</item>
         <item name="colorOnSurfaceVariant">@color/white</item>
         <item name="colorControlHighlight">@color/white</item>
+        <item name="android:textColorPrimary">@color/white</item>
     </style>
 </resources>