🩹(react) update stylesheet to use modern SASS

Replaced deprecated '@import' with '@use' to align with best practices.
Refactored stylesheet to behave as a partial, enhancing SASS compilation
efficiency.

packages/react/src/components/Accessibility/index.scss

@@ -1,12 +0,0 @@
-.offscreen {
-  position: absolute;
-  width: 1px;
-  height: 1px;
-  padding: 0;
-  margin: -1px;
-  overflow: hidden;
-  clip: rect(0, 0, 0, 0);
-  clip-path: inset(50%);
-  white-space: nowrap;
-  border: 0;
-}

packages/react/src/components/Forms/DatePicker/_index.scss

@@ -1,4 +1,4 @@
-@use 'src/utils';
+@use 'src/utils' as *;
 
 
 .c__date-picker {

packages/react/src/components/Forms/Select/_index.scss

@@ -1,4 +1,4 @@
-@use 'src/utils';
+@use 'src/utils' as *;;
 
 .c__select {
   position: relative;

packages/react/src/components/Popover/_index.scss

@@ -1,4 +1,4 @@
-@use 'src/utils';
+@use 'src/utils' as *;
 
 
 .c__popover {

packages/react/src/fonts.scss

@@ -1 +1 @@
-@import "@fontsource-variable/roboto-flex";
+@use "@fontsource-variable/roboto-flex";

packages/react/src/icons.scss

@@ -1,4 +1,4 @@
-@import "@fontsource/material-icons";
+@use "@fontsource/material-icons";
 
 .material-icons {
   font-family: 'Material Icons';

packages/react/src/index.scss

@@ -1,22 +1,25 @@
-@import "cunningham-tokens";
-@import '@openfun/cunningham-tokens/default-tokens';
-@import './utils';
-@import './components/Accessibility';
-@import './components/Button';
-@import './components/DataGrid';
-@import './components/Forms/Checkbox';
-@import './components/Forms/Field';
-@import './components/Forms/FileUploader';
-@import './components/Forms/Radio';
-@import './components/Forms/TextArea';
-@import './components/Forms/Input';
-@import './components/Forms/LabelledBox';
-@import './components/Forms/Select';
-@import './components/Forms/Switch';
-@import './components/Forms/DatePicker';
-@import './components/Loader';
-@import './components/Pagination';
-@import './components/Popover';
+
+@forward "./utils";
+
+@use "cunningham-tokens";
+@use "@openfun/cunningham-tokens/default-tokens";
+
+@use "./components/Accessibility";
+@use "./components/Button";
+@use "./components/DataGrid";
+@use "./components/Forms/Checkbox";
+@use "./components/Forms/Field";
+@use "./components/Forms/FileUploader";
+@use "./components/Forms/Radio";
+@use './components/Forms/TextArea';
+@use "./components/Forms/Input";
+@use "./components/Forms/LabelledBox";
+@use "./components/Forms/Select";
+@use "./components/Forms/Switch";
+@use "./components/Forms/DatePicker";
+@use "./components/Loader";
+@use "./components/Pagination";
+@use "./components/Popover";
 
 body {
   font-family: var(--c--theme--font--families--base);