Remove bringup: true from web tests. (#160788)

We should make this a blocking CI step ASAP.
diff --git a/engine/src/flutter/.ci.yaml b/engine/src/flutter/.ci.yaml
index 0f84c6a..e9dadec 100644
--- a/engine/src/flutter/.ci.yaml
+++ b/engine/src/flutter/.ci.yaml
@@ -399,7 +399,6 @@
       cores: "8"
 
   - name: Linux linux_web_engine_tests
-    bringup: true
     recipe: engine_v2/engine_v2
     timeout: 120
     properties: