Reenable NexusLowRes API 29 (#136686)

Reenable the NexusLowRes API version 29 tests. 

*List which issues are fixed by this PR. You must list at least one issue.*
fixes https://buganizer.corp.google.com/issues/302753598
fixes flutter/flutter#135784

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

.ci.yaml

@@ -449,9 +449,7 @@ targets:
           "--device", "model=redfin,version=30"
         ]
       # TODO(flutter/flutter#123331): This device is flaking.
-      # "--device", "model=Nexus6P,version=25",
-      # TODO(flutter/flutter#135784): This device is flaking.
-      # "--device", "model=NexusLowRes,version=29",
+      # "--device", "model=Nexus6P,version=25"
       virtual_devices: >-
         [
           "--device", "model=Nexus5,version=21",
@@ -460,7 +458,8 @@ targets:
           "--device", "model=Nexus5,version=24",
           "--device", "model=Nexus6P,version=25",
           "--device", "model=Nexus6P,version=26",
-          "--device", "model=Nexus6P,version=27"
+          "--device", "model=Nexus6P,version=27",
+          "--device", "model=NexusLowRes,version=29"
         ]
 
   - name: Linux firebase_android_embedding_v2_smoke_test
@@ -481,9 +480,7 @@ targets:
           "--device", "model=griffin,version=24"
         ]
       # TODO(flutter/flutter#123331): This device is flaking.
-      # "--device", "model=Nexus6P,version=25",
-      # TODO(flutter/flutter#135784): This device is flaking.
-      # "--device", "model=NexusLowRes,version=29",
+      # "--device", "model=Nexus6P,version=25"
       virtual_devices: >-
         [
           "--device", "model=Nexus5,version=21",
@@ -491,7 +488,8 @@ targets:
           "--device", "model=Nexus5,version=23",
           "--device", "model=Nexus6P,version=25",
           "--device", "model=Nexus6P,version=26",
-          "--device", "model=Nexus6P,version=27"
+          "--device", "model=Nexus6P,version=27",
+          "--device", "model=NexusLowRes,version=29"
         ]
 
   - name: Linux firebase_release_smoke_test
@@ -512,9 +510,7 @@ targets:
           "--device", "model=griffin,version=24"
         ]
       # TODO(flutter/flutter#123331): This device is flaking.
-      # "--device", "model=Nexus6P,version=25",
-      # TODO(flutter/flutter#135784): This device is flaking.
-      # "--device", "model=NexusLowRes,version=29",
+      # "--device", "model=Nexus6P,version=25"
       virtual_devices: >-
         [
           "--device", "model=Nexus5,version=21",
@@ -522,7 +518,8 @@ targets:
           "--device", "model=Nexus5,version=23",
           "--device", "model=Nexus6P,version=25",
           "--device", "model=Nexus6P,version=26",
-          "--device", "model=Nexus6P,version=27"
+          "--device", "model=Nexus6P,version=27",
+          "--device", "model=NexusLowRes,version=29"
         ]
 
   - name: Linux flutter_packaging_test