Bump sassc-embedded from 1.70.1 to 1.80.1

Note: Since we update to 1.80.1 deprecation warnings are appear when execute the assets:precompile command.
In order to silence this deprecation, we add silence_deprecation option in sass.rb initializer.

The code has also been updated to remove the deprecation warnings that appeared related to the function
darken(), lighten() and "Using / for division" instead of the function calc().

Bumps [sassc-embedded](https://github.com/sass-contrib/sassc-embedded-shim-ruby) from 1.70.1 to 1.80.1.
- [Commits](https://github.com/sass-contrib/sassc-embedded-shim-ruby/compare/v1.70.1...v1.80.1)

---
updated-dependencies:
- dependency-name: sassc-embedded
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

config/initializers/sass.rb

@@ -1,8 +1,10 @@
-# TODO: remove once we upgrade Foundation and Font Awesome
+# TODO: Remove quiet_deps once we upgrade Foundation and Font Awesome,
+# and remove silence_deprecations once we migrate away from Sass @import rules,
+# which will be removed in Dart Sass 3.0.0.
 SassC::Engine.class_eval do
   alias_method :original_initialize, :initialize
 
   def initialize(template, options = {})
-    original_initialize(template, options.merge(quiet_deps: true))
+    original_initialize(template, options.merge(quiet_deps: true, silence_deprecations: [:import]))
   end
 end