Adopt @labkey/themes version 1.9.3 to remove GWT styles (#7664)

#### Rationale
We don't need styling for GWT anymore.

#### Related Pull Requests
- LabKey/labkey-ui-components#2000

#### Changes
- Bump to the version that no longer includes GWT CSS

#### Tasks 📍
- [x] Claude Code Review
- ~Manual Testing~
- ~Test Automation~

---------

Co-authored-by: labkey-nicka <[email protected]>

Author: labkey-jeckels

core/package-lock.json

@@ -54,7 +54,7 @@
   },
   "dependencies": {
     "@labkey/components": "7.35.2",
-    "@labkey/themes": "1.9.2"
+    "@labkey/themes": "1.9.3"
   },
   "devDependencies": {
     "@labkey/build": "9.1.3",