remove @firebase/testing from the repo (#3951)

* remove @firebase/testing from the repo

* skip deleted projects

* fix script

Author: Feiyang1

.changeset/config.json

@@ -21,7 +21,6 @@
     "@firebase/installations-types-exp",
     "@firebase/performance-exp",
     "@firebase/performance-types-exp",
-    "@firebase/testing",
     "firebase-exp",
     "@firebase/app-compat",
     "@firebase/changelog-generator",

.github/workflows/test-changed-misc.yml

@@ -1,4 +1,4 @@
-name: Test rxFire, @firebase/testing and @firebase/rules-unit-testing
+name: Test rxFire and @firebase/rules-unit-testing
 
 on: pull_request