fix(styles): downgrade sass version as there is an issue with @extend (…

…carbon-design-system#9973)

### Related Ticket(s)

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### Description

There seems to be an issue with `@extend` in the recent upgrade of `sass`. Downgrading `sass` version until there is fix

### Changelog

**Changed**

- downgrade sass back to `~1.40.0`

**Removed**

- band-aid fixes that should be resolved with the `sass` downgrade

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web-components/packages/carbon-web-components/package.json

@@ -193,7 +193,7 @@
     "rollup-plugin-multi-input": "^1.3.1",
     "rollup-plugin-terser": "^7.0.2",
     "rtlcss": "^3.0.0",
-    "sass": "~1.57.0",
+    "sass": "~1.40.0",
     "sass-loader": "^10.0.0",
     "strip-comments": "^1.0.0",
     "style-loader": "^2.0.0",

web-components/packages/carbon-web-components/src/components/breadcrumb/breadcrumb.scss

@@ -17,13 +17,6 @@ $css--plex: true !default;
 
 :host(#{$prefix}-breadcrumb-item) {
   @extend .#{$prefix}--breadcrumb-item;
-
-  // TODO: see if we can remove this ::after section after v11 upgrade
-  &::after {
-    margin-left: $spacing-03;
-    color: $text-primary;
-    content: '/';
-  }
 }
 
 :host(#{$prefix}-breadcrumb-overflow-menu) {

web-components/packages/carbon-web-components/src/components/modal/modal.scss

@@ -74,10 +74,6 @@
 
 :host(#{$prefix}-modal[open]) {
   @extend .#{$prefix}--modal, .is-visible;
-
-  // TODO: look into if following two lines are necessary after v11 upgrade
-  opacity: 1;
-  visibility: inherit;
 }
 
 :host(#{$prefix}-modal-header) {