feat(ui): revise image viewer

- Viewer only exists on Generation tab
- Viewer defaults to open
- When clicking the Control Layers tab on the left panel, close the viewer (i.e. open the CL editor)
- Do not switch to editor when adding layers (this is handled by clicking the Control Layers tab)
- Do not open viewer when single-clicking images in gallery
- _Do_ open viewer when _double_-clicking images in gallery
- Do not change viewer state when switching between app tabs (this no longer makes sense; the viewer only exists on generation tab)
- Change the button to a drop down menu that states what you are currently doing, e.g. Viewing vs Editing

invokeai/frontend/web/src/common/components/IAIDndImage.tsx

@@ -70,6 +70,7 @@ const IAIDndImage = (props: IAIDndImageProps) => {
     onMouseOver,
     onMouseOut,
     dataTestId,
+    ...rest
   } = props;
 
   const [isHovered, setIsHovered] = useState(false);
@@ -138,6 +139,7 @@ const IAIDndImage = (props: IAIDndImageProps) => {
           minH={minSize ? minSize : undefined}
           userSelect="none"
           cursor={isDragDisabled || !imageDTO ? 'default' : 'pointer'}
+          {...rest}
         >
           {imageDTO && (
             <Flex