[new-prs-labeler] Add "DXContainer" patterns to the backend:DirectX label (#85446)

This should make sure PRs like #84409 get labelled.

Author: bogner

.github/new-prs-labeler.yml

@@ -629,6 +629,8 @@ backend:DirectX:
   - '**/*DirectX*/**'
   - '**/*DXIL*/**'
   - '**/*dxil*/**'
+  - '**/*DXContainer*'
+  - '**/*DXContainer*/**'
 
 backend:SPIR-V:
   - clang/lib/Driver/ToolChains/SPIRV.*