[devicelab] mark ios transition_perf as non-flaky (#58499)

diff --git a/dev/devicelab/manifest.yaml b/dev/devicelab/manifest.yaml
index 73ba319..49c9fdb 100644
--- a/dev/devicelab/manifest.yaml
+++ b/dev/devicelab/manifest.yaml
@@ -491,7 +491,6 @@
       32-bit iOS (iPhone 4S).
     stage: devicelab_ios
     required_agent_capabilities: ["mac/ios32"]
-    flaky: true # TODO(jmagman): https://github.com/flutter/flutter/issues/57225
 
   flavors_test_ios:
     description: >
@@ -572,7 +571,6 @@
       iOS.
     stage: devicelab_ios
     required_agent_capabilities: ["mac/ios"]
-    flaky: true # TODO(jmagman): https://github.com/flutter/flutter/issues/57225
 
   hello_world_ios__compile:
     description: >