github: workflow: use 24.04LTS for testbench build

The 24.10 runner availability is not great and 24.10 is not
strictly needed, so use 24.04LTS instead.

Signed-off-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>

Author: kv2019i

.github/workflows/testbench.yml

@@ -30,7 +30,7 @@ on:
 
 jobs:
   build-and-test:
-    runs-on: ubuntu-24.10
+    runs-on: ubuntu-24.04
 
     steps:
       - name: Checkout SOF repository (PR source)