Mark no longer flakey tests as bringup:false (#126281)

This is a result of auditing the ci.yaml tests marked as bringup true and determining which ones were still flakey. 
Each commit markes one tests as non flakey along with a link of proof of the lack of flakes. 

- Mark new_gallery_impeller__transition_perf as not flakey, #124699 closed, not recent flakes
- No failures in 500 runs for Staging_build_linux analyze https://ci.chromium.org/p/flutter/builders/staging/Staging_build_linux%20analyze\?cursor\=id%3E8782771663962116337\&limit\=200
- No flakes in 600 builds https://ci.chromium.org/p/flutter/builders/staging/Linux%20flutter_packaging_test\?cursor\=id%3E8787892377160059793\&limit\=200
- No flakes in 600 builds https://ci.chromium.org/p/flutter/builders/staging/Mac%20flutter_packaging_test\?cursor\=id%3E8787870631931126673\&limit\=200
- No flakes in 600 builds https://ci.chromium.org/p/flutter/builders/staging/Mac_arm64%20flutter_packaging_test\?cursor\=id%3E8787809799161254193\&limit\=200

#124699 is the only closed bug that was linked for a test that is no longer flakey. Closed status helps the case that flakes are no longer an issue.

Author: reidbaker

.ci.yaml

@@ -2194,7 +2194,6 @@ targets:
       task_name: new_gallery__transition_perf
 
   - name: Linux_android new_gallery_impeller__transition_perf
-    bringup: true # Flaky https://github.com/flutter/flutter/issues/124699
     recipe: devicelab/devicelab_drone
     presubmit: false
     timeout: 60
@@ -4835,7 +4834,7 @@ targets:
     recipe: packaging/packaging
     timeout: 60
     scheduler: release
-    bringup: true
+    bringup: true # https://github.com/flutter/flutter/issues/126286
     enabled_branches:
       - beta
       - stable
@@ -4850,7 +4849,6 @@ targets:
     recipe: packaging/packaging
     timeout: 60
     scheduler: release
-    bringup: true
     enabled_branches:
       - beta
       - stable
@@ -4867,7 +4865,6 @@ targets:
     recipe: packaging/packaging
     timeout: 60
     scheduler: release
-    bringup: true
     enabled_branches:
       - beta
       - stable