build(deps-dev): remove @vitest/ui (#990)

### Summary of Changes

Remove `@vitest/ui`. Webstorm's test with coverage is faster and shows
results directly in the IDE. Developers who still need it can install it
locally.

package.json

@@ -14,8 +14,7 @@
         "build:clean": "npm run clean && npm run build",
         "watch": "concurrently -n tsc,cli,lang,vscode,eda -c blue,yellow,red,green \"tsc -b tsconfig.json\" \"npm run watch -w=@safe-ds/cli\" \"npm run watch -w=@safe-ds/lang\" \"npm run watch -w=safe-ds\" \"npm run watch -w=@safe-ds/eda\"",
         "test": "vitest",
-        "test-with-coverage": "vitest --coverage",
-        "test-ui": "vitest --ui --coverage"
+        "test-with-coverage": "vitest --coverage"
     },
     "devDependencies": {
         "@lars-reimann/eslint-config-svelte": "^7.0.0",
@@ -26,7 +25,6 @@
         "@semantic-release/npm": "^12.0.0",
         "@tsconfig/svelte": "^5.0.4",
         "@vitest/coverage-v8": "^1.4.0",
-        "@vitest/ui": "^1.2.2",
         "concurrently": "^8.2.2",
         "conventional-changelog-conventionalcommits": "^7.0.2",
         "semantic-release": "^23.0.6",