refactor(): add scss usage deprecation warning (#19238)

core/src/themes/ionic.deprecation.scss

@@ -0,0 +1,5 @@
+$IONIC: false !default;
+
+@if not $IONIC {
+  @warn "[DEPRECATED] SCSS within ionic/core should not be imported. Next major release will remove all scss support.";
+}

core/src/themes/ionic.functions.color.scss

@@ -1,3 +1,5 @@
+@import "./ionic.deprecation";
+
 // Gets the active color's css variable from a variation. Alpha is optional.
 // --------------------------------------------------------------------------------------------
 // Example usage:

core/src/themes/ionic.functions.string.scss

@@ -1,3 +1,4 @@
+@import "./ionic.deprecation";
 
 // String Utility Functions
 // --------------------------------------------------------------------------------

core/src/themes/ionic.mixins.scss

@@ -1,3 +1,4 @@
+@import "./ionic.deprecation";
 
 @mixin input-cover() {
   @include position(0, null, null, 0);

core/src/themes/ionic.skip-warns.scss

@@ -0,0 +1 @@
+$IONIC: true;

core/src/themes/ionic.theme.default.scss

@@ -1,3 +1,5 @@
+@import "./ionic.deprecation";
+
 // Ionic Theme
 // -------------------------------------------------------------------------------------------
 // This file contains the theme variables shared

core/stencil.config.ts

@@ -64,7 +64,9 @@ export const config: Config = {
     ]},
   ],
   plugins: [
-    sass()
+    sass({
+      injectGlobalPaths: ['src/themes/ionic.skip-warns.scss']
+    })
   ],
   outputTargets: [
     {