fix(ui): excise most zIndexs

our stacking contexts are accurate, `zIndex` isn't needed

invokeai/frontend/web/src/features/system/components/ProgressBar.tsx

@@ -36,7 +36,6 @@ const ProgressBar = () => {
       aria-label={t('accessibility.invokeProgressBar')}
       isIndeterminate={isProcessing && !currentStatusHasSteps}
       height={PROGRESS_BAR_THICKNESS}
-      zIndex={99}
     />
   );
 };

invokeai/frontend/web/src/features/ui/components/FloatingGalleryButton.tsx

@@ -44,7 +44,6 @@ const FloatingGalleryButton = () => {
         pos: 'absolute',
         top: '50%',
         transform: 'translate(0, -50%)',
-        zIndex: 31,
         p: 0,
         insetInlineEnd: 0,
         px: 3,

invokeai/frontend/web/src/features/ui/components/FloatingParametersPanelButtons.tsx

@@ -73,7 +73,6 @@ const FloatingParametersPanelButtons = () => {
     <Flex
       pos="absolute"
       transform="translate(0, -50%)"
-      zIndex={20}
       minW={8}
       top="50%"
       insetInlineStart="4.5rem"

invokeai/frontend/web/src/features/ui/components/common/ResizableDrawer/ResizableDrawer.tsx

@@ -142,7 +142,7 @@ const ResizableDrawer = ({
       direction={slideDirection}
       in={isOpen}
       motionProps={{ initial: false }}
-      style={{ zIndex: 99, width: 'full' }}
+      style={{ width: 'full' }}
     >
       <Box
         ref={outsideClickRef}