remove useless test

Author: Siedlerchr

src/test/java/org/jabref/logic/openoffice/style/StyleLoaderTest.java

@@ -48,11 +48,6 @@ public void throwNPEWithNullLayoutPreferences() {
         assertThrows(NullPointerException.class, () -> loader = new StyleLoader(mock(OpenOfficePreferences.class), null));
     }
 
-    @Test
-    public void throwNPEWithNullCharset() {
-        assertThrows(NullPointerException.class, () -> loader = new StyleLoader(mock(OpenOfficePreferences.class), layoutPreferences));
-    }
-
     @Test
     public void testGetStylesWithEmptyExternal() {
         preferences.setExternalStyles(Collections.emptyList());