feat(theme): export light theme tokens (#28802)

Issue number: Internal

---------

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issue. -->

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## What is the current behavior?
<!-- Please describe the current behavior that you are modifying. -->
The light theme tokens are included in the starter apps but not in Ionic
Framework itself.

## What is the new behavior?
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this PR. -->

- The light mode tokens are bundled with Ionic Framework. This allows
developers to always have the light mode accessible to them including
the tokens.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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  2. Update the BREAKING.md file with the breaking change.
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## Other information

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screenshots of how the component looks before and after the change. -->

---------

Co-authored-by: ionitron <hi@ionicframework.com>

core/src/css/core.scss

@@ -2,6 +2,80 @@
 @import "../components/menu/menu.ios.vars";
 @import "../components/menu/menu.md.vars";
 
+:root {
+  /** primary **/
+  --ion-color-primary: #0054e9;
+  --ion-color-primary-rgb: 0, 84, 233;
+  --ion-color-primary-contrast: #ffffff;
+  --ion-color-primary-contrast-rgb: 255, 255, 255;
+  --ion-color-primary-shade: #004acd;
+  --ion-color-primary-tint: #1a65eb;
+
+  /** secondary **/
+  --ion-color-secondary: #0163aa;
+  --ion-color-secondary-rgb: 1, 99, 170;
+  --ion-color-secondary-contrast: #ffffff;
+  --ion-color-secondary-contrast-rgb: 255, 255, 255;
+  --ion-color-secondary-shade: #015796;
+  --ion-color-secondary-tint: #1a73b3;
+
+  /** tertiary **/
+  --ion-color-tertiary: #6030ff;
+  --ion-color-tertiary-rgb: 96, 48, 255;
+  --ion-color-tertiary-contrast: #ffffff;
+  --ion-color-tertiary-contrast-rgb: 255, 255, 255;
+  --ion-color-tertiary-shade: #542ae0;
+  --ion-color-tertiary-tint: #7045ff;
+
+  /** success **/
+  --ion-color-success: #2dd55b;
+  --ion-color-success-rgb: 45, 213, 91;
+  --ion-color-success-contrast: #000000;
+  --ion-color-success-contrast-rgb: 0, 0, 0;
+  --ion-color-success-shade: #28bb50;
+  --ion-color-success-tint: #42d96b;
+
+  /** warning **/
+  --ion-color-warning: #ffc409;
+  --ion-color-warning-rgb: 255, 196, 9;
+  --ion-color-warning-contrast: #000000;
+  --ion-color-warning-contrast-rgb: 0, 0, 0;
+  --ion-color-warning-shade: #e0ac08;
+  --ion-color-warning-tint: #ffca22;
+
+  /** danger **/
+  --ion-color-danger: #c5000f;
+  --ion-color-danger-rgb: 197, 0, 15;
+  --ion-color-danger-contrast: #ffffff;
+  --ion-color-danger-contrast-rgb: 255, 255, 255;
+  --ion-color-danger-shade: #ad000d;
+  --ion-color-danger-tint: #cb1a27;
+
+  /** dark **/
+  --ion-color-dark: #2f2f2f;
+  --ion-color-dark-rgb: 47, 47, 47;
+  --ion-color-dark-contrast: #ffffff;
+  --ion-color-dark-contrast-rgb: 255, 255, 255;
+  --ion-color-dark-shade: #292929;
+  --ion-color-dark-tint: #444444;
+
+  /** medium **/
+  --ion-color-medium: #5f5f5f;
+  --ion-color-medium-rgb: 95, 95, 95;
+  --ion-color-medium-contrast: #ffffff;
+  --ion-color-medium-contrast-rgb: 255, 255, 255;
+  --ion-color-medium-shade: #545454;
+  --ion-color-medium-tint: #6f6f6f;
+
+  /** light **/
+  --ion-color-light: #f6f8fc;
+  --ion-color-light-rgb: 246, 248, 252;
+  --ion-color-light-contrast: #000000;
+  --ion-color-light-contrast-rgb: 0, 0, 0;
+  --ion-color-light-shade: #d8dade;
+  --ion-color-light-tint: #f7f9fc;
+}
+
 // Ionic Font Family
 // --------------------------------------------------