Fix uncaught TypeError in ext/console (css styling)

[zachauten]

When using css coloring in the console, non-color values should be ignored rather than throw exceptions.
Fixes #13469

[kt3k]

@zachauten
Thanks for the contribution!

Confirmed this fixes the bug. Nice!

But I think we need another test case like the below to check an invalid color doesn't cause the uncaught error:

Deno.test(function consoleLogShouldNotThrowErrorWhenInvalidCssColorsAreGiven() {
  mockConsole((console, out) => {
    console.log("%cfoo", "color: foo; background-color: bar;");
    assertEquals(out.toString(), "foo\n");
  });
});

[lucacasonato]

@zachauten Do you want to add that test case, or finish this PR up for you?

[zachauten]

@kt3k @lucacasonato Added!

[kt3k]

@zachauten Thanks for the update! LGTM