Remove build_gallery tests (#74463)

* Remove build_gallery tests

* Re-add deploy_gallery.sh

dev/prod_builders.json

@@ -120,12 +120,6 @@
          "task_name": "linux_docs",
          "flaky": false
       },
-      {
-         "name": "Linux build_gallery",
-         "repo": "flutter",
-         "task_name": "linux_build_gallery",
-         "flaky": false
-      },
       {
          "name": "Linux build_tests",
          "repo": "flutter",
@@ -696,12 +690,6 @@
          "task_name": "mac_build_tests",
          "flaky": false
       },
-      {
-         "name": "Mac build_gallery",
-         "repo": "flutter",
-         "task_name": "mac_build_gallery",
-         "flaky": true
-      },
       {
          "name": "Mac customer_testing",
          "repo": "flutter",

dev/try_builders.json

@@ -32,12 +32,6 @@
          "enabled":true,
          "run_if":["dev/", "packages/flutter/", "packages/flutter_test/", "packages/flutter_drive/", "packages/flutter_localizations/", "bin/"]
       },
-      {
-         "name":"Linux build_gallery",
-         "repo":"flutter",
-         "task_name":"linux_build_gallery",
-         "enabled":true
-      },
       {
          "name":"Linux framework_tests",
          "repo":"flutter",
@@ -220,12 +214,6 @@
          "task_name":"mac_customer_testing",
          "enabled":true
       },
-      {
-         "name":"Mac build_gallery",
-         "repo":"flutter",
-         "task_name":"mac_build_gallery",
-         "enabled":false
-      },
       {
          "name":"Mac framework_tests",
          "repo":"flutter",