Add Light High Contrast theme (#143398)

* Add light HC theme and split quick pick options to light and dark

* Update colorizer tests

* Fix default HC name and add Beta tag to light HC theme

* Revert prettier updates

extensions/theme-defaults/package.json

@@ -42,6 +42,12 @@
         "label": "%hcColorThemeLabel%",
         "uiTheme": "hc-black",
         "path": "./themes/hc_black.json"
+      },
+      {
+        "id": "Light High Contrast",
+        "label": "%lightHcColorThemeLabel%",
+        "uiTheme": "hc-black",
+        "path": "./themes/hc_light.json"
       }
     ],
     "iconThemes": [