Add @jupyterlab/theme-dark-high-contrast-extension (#7331)

* Add `@jupyterlab/theme-dark-high-contrast-extension`

* Update Playwright Snapshots

* Update Playwright Snapshots

* undo unrelated snapshot update

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: jtpio

app/package.json

@@ -92,6 +92,7 @@
     "@jupyterlab/terminal": "~4.2.0-beta.1",
     "@jupyterlab/terminal-extension": "~4.2.0-beta.1",
     "@jupyterlab/theme-dark-extension": "~4.2.0-beta.1",
+    "@jupyterlab/theme-dark-high-contrast-extension": "~4.2.0-beta.1",
     "@jupyterlab/theme-light-extension": "~4.2.0-beta.1",
     "@jupyterlab/toc-extension": "~6.2.0-beta.1",
     "@jupyterlab/tooltip": "~4.2.0-beta.1",
@@ -171,6 +172,7 @@
     "@jupyterlab/shortcuts-extension": "~5.0.0-beta.1",
     "@jupyterlab/terminal-extension": "~4.2.0-beta.1",
     "@jupyterlab/theme-dark-extension": "~4.2.0-beta.1",
+    "@jupyterlab/theme-dark-high-contrast-extension": "~4.2.0-beta.1",
     "@jupyterlab/theme-light-extension": "~4.2.0-beta.1",
     "@jupyterlab/toc-extension": "~6.2.0-beta.1",
     "@jupyterlab/tooltip-extension": "~4.2.0-beta.1",
@@ -295,6 +297,7 @@
         "@jupyterlab/terminal-extension": true,
         "@jupyterlab/theme-light-extension": true,
         "@jupyterlab/theme-dark-extension": true,
+        "@jupyterlab/theme-dark-high-contrast-extension": true,
         "@jupyterlab/translation-extension": true,
         "@jupyterlab/ui-components-extension": true,
         "@jupyterlab/hub-extension": true

ui-tests/test/menus.spec.ts-snapshots/opened-menu-settings-theme-chromium-linux.png

@@ -2103,6 +2103,7 @@ __metadata:
     "@jupyterlab/shortcuts-extension": ~5.0.0-beta.1
     "@jupyterlab/terminal-extension": ~4.2.0-beta.1
     "@jupyterlab/theme-dark-extension": ~4.2.0-beta.1
+    "@jupyterlab/theme-dark-high-contrast-extension": ~4.2.0-beta.1
     "@jupyterlab/theme-light-extension": ~4.2.0-beta.1
     "@jupyterlab/toc-extension": ~6.2.0-beta.1
     "@jupyterlab/tooltip-extension": ~4.2.0-beta.1
@@ -4181,6 +4182,17 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@jupyterlab/theme-dark-high-contrast-extension@npm:~4.2.0-beta.1":
+  version: 4.2.0-beta.1
+  resolution: "@jupyterlab/theme-dark-high-contrast-extension@npm:4.2.0-beta.1"
+  dependencies:
+    "@jupyterlab/application": ^4.2.0-beta.1
+    "@jupyterlab/apputils": ^4.3.0-beta.1
+    "@jupyterlab/translation": ^4.2.0-beta.1
+  checksum: 6d282b3a7d19b32a608164489bd7f6b1bd9733fb2d3120c6f4fe8af2deaaf54cb57f2d70859e0b4123b3e45b7275852cc31868115768b4deba9e8e94a849a73b
+  languageName: node
+  linkType: hard
+
 "@jupyterlab/theme-light-extension@npm:~4.2.0-beta.1":
   version: 4.2.0-beta.1
   resolution: "@jupyterlab/theme-light-extension@npm:4.2.0-beta.1"