ci: LibreOffice builds formula objects, and node strips the TS import

libreoffice-writer alone has no Math component, so Writer dropped every formula
it imported — Word's own OMML included — and the fuzz leg saw the loss.
node 20 cannot import tests/schemaValidate.ts, which the monkey run does; 24
strips the types. node 20 is end of life anyway.

.github/workflows/deploy.yml

@@ -27,7 +27,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: 20
+          node-version: 24
           cache: npm
       - run: npm ci
       - run: npm run build