Fix CI: Remove frozen lockfile for postguard-tb-addon

The submodule's yarn.lock is out of sync. Use regular yarn install to allow lockfile updates during build.

Author: rubenhensen

.github/workflows/docker-build.yml

@@ -38,7 +38,7 @@ jobs:
       - name: Build postguard-tb-addon
         working-directory: ./postguard-tb-addon
         run: |
-          yarn install --frozen-lockfile
+          yarn install
           yarn build
 
       - name: Build cryptify frontend