Remove wgpu::CreatePipelineAsyncStatus::Error

It is no longer used in Chromium and the ::ValidationError and
::InternalError should be used instead.

Fixed: chromium:1404422
Change-Id: I7ecb1e23cfedc8f16f91431ac8b9ec8a9bbf2933
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/119461
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Auto-Submit: Corentin Wallez <cwallez@chromium.org>

dawn.json

@@ -975,8 +975,7 @@
             {"value": 2, "name": "internal error"},
             {"value": 3, "name": "device lost"},
             {"value": 4, "name": "device destroyed"},
-            {"value": 5, "name": "unknown"},
-            {"value": 6, "name": "error"}
+            {"value": 5, "name": "unknown"}
         ]
     },
     "create render pipeline async callback": {