feat(loading): use gray tokens

Author: thetaPC

core/src/components/loading/loading.ios.vars.scss

@@ -43,7 +43,7 @@ $loading-ios-translucent-background-color: rgba($background-color-rgb, $loading-
 $loading-ios-content-font-weight: bold;
 
 /// @prop - Color of the loading spinner
-$loading-ios-spinner-color: $text-color-step-400;
+$loading-ios-spinner-color: var(--ion-color-gray-600);
 
 /// @prop - Filter of the translucent loading
 $loading-ios-translucent-filter: saturate(180%) blur(20px);

core/src/components/loading/loading.md.vars.scss

@@ -28,10 +28,10 @@ $loading-md-max-height: 90%;
 $loading-md-border-radius: 2px;
 
 /// @prop - Text color of the loading wrapper
-$loading-md-text-color: $text-color-step-150;
+$loading-md-text-color: var(--ion-color-gray-850);
 
 /// @prop - Background of the loading wrapper
-$loading-md-background: $background-color-step-50;
+$loading-md-background: var(--ion-color-gray-50);
 
 /// @prop - Box shadow color of the loading wrapper
 $loading-md-box-shadow-color: rgba(0, 0, 0, 0.4);