Fix rgba alpha channel parsing

DEVSIX-2673

Author: Dmitry Radchuk

kernel/src/main/java/com/itextpdf/kernel/colors/WebColors.java

@@ -301,6 +301,9 @@ public static float[] getRGBAColor(String name) {
                 parseRGBColors(color, tok);
                 if (tok.hasMoreTokens()) {
                     color[3] = getAlphaChannelValue(tok.nextToken());
+                    if (tok.hasMoreTokens()) {
+                        throw new IllegalArgumentException("Too many arguments");
+                    }
                 }
             } else if (NAMES.containsKey(colorName)) {
                 int[] intColor = NAMES.get(colorName);

kernel/src/test/java/com/itextpdf/kernel/colors/WebColorsTest.java

@@ -204,6 +204,11 @@ public void getRGBAColorWithExceptionDuringParsing() {
         Assertions.assertNull(resultCmyk);
     }
 
+    @Test
+    public void getRGBAColorWithExceptionDuringParsingAlpha() {
+        float[] resultCmyk = WebColors.getRGBAColor("rgba(44, 100, 0, 0,75)");
+        Assertions.assertNull(resultCmyk);
+    }
 
 
     @Test

svg/src/test/java/com/itextpdf/svg/renderers/OpacityTest.java

@@ -57,7 +57,6 @@ public void testOpacityComplex() throws IOException, InterruptedException {
   }
 
   @Test
-  //TODO: update after DEVSIX-2673 fix
   public void testRGBA() throws IOException, InterruptedException {
     convertAndCompare(SOURCE_FOLDER, DESTINATION_FOLDER, "svg_rgba");
   }