Define click behavior for imagemaps

[barancev]

This sample of code throws "element not interactable" in Firefox

driver.get("https://output.jsbin.com/gegatap");
driver.findElement(By.id("rectG")).click();

See https://bugzilla.mozilla.org/show_bug.cgi?id=1502636

As noted in comments

"This only fails for clicks when having the webdriver compat mode enabled. The reason is that the element is basically not visible but overlays the specified image reference, and as such doesn't appear in the paint tree.

As such the check should be performed against the referenced image but not the area or map element."