Remove overall vcpkg cache of all installed packages

This means we rely on the caches of each individual binary package, rather than the entire collection of all of them.

.github/workflows/build.yml

@@ -30,13 +30,6 @@ jobs:
           core.exportVariable('ACTIONS_CACHE_URL', process.env.ACTIONS_CACHE_URL || '');
           core.exportVariable('ACTIONS_RUNTIME_TOKEN', process.env.ACTIONS_RUNTIME_TOKEN || '');
 
-    - name: Restore vcpkg dependency cache
-      uses: actions/cache@v4
-      id: cache
-      with:
-        path: vcpkg_installed
-        key: ${{ runner.os }}-${{ matrix.platform }}-${{ hashFiles('vcpkg.json') }}
-
     - name: Restore incremental build cache
       uses: actions/cache/restore@v4
       if: github.ref != format('refs/heads/{0}', github.event.repository.default_branch)