feature: update ado yamls to use pool-ubuntu-2404

Author: DanielMicrosoft

.azure-pipelines/templates/variables.yml

@@ -1,5 +1,5 @@
 variables:
-  ubuntu_pool: 'pool-ubuntu-2204'
+  ubuntu_pool: 'pool-ubuntu-2404'
   ubuntu_multi_core_pool: 'pool-ubuntu-latest-multi-core'
   windows_pool: 'pool-windows-2019'
   ubuntu_arm64_pool: 'pool-ubuntu-latest-arm64'