fix(ci): add libsecret-1-dev to Linux build dependencies

Fixes build error:
  CMake Error: The following required packages were not found:
   - libsecret-1>=0.18.4

This dependency is required by flutter_secure_storage_linux plugin.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: 777genius

.github/workflows/build-linux.yml

@@ -45,7 +45,8 @@ jobs:
             libpango1.0-dev \
             libgdk-pixbuf2.0-dev \
             libappindicator3-dev \
-            libkeybinder-3.0-dev
+            libkeybinder-3.0-dev \
+            libsecret-1-dev
 
       - name: Install Python dependencies
         run: |