revert settings

Author: cherylEnkidu

Firestore/Example/Firestore.xcodeproj/xcshareddata/xcschemes/Firestore_Example_iOS.xcscheme

@@ -89,18 +89,6 @@
             ReferencedContainer = "container:Firestore.xcodeproj">
          </BuildableReference>
       </BuildableProductRunnable>
-      <EnvironmentVariables>
-         <EnvironmentVariable
-            key = "PROJECT_ID"
-            value = "firestore-sdk-nightly"
-            isEnabled = "YES">
-         </EnvironmentVariable>
-         <EnvironmentVariable
-            key = "TARGET_BACKEND"
-            value = "nightly"
-            isEnabled = "YES">
-         </EnvironmentVariable>
-      </EnvironmentVariables>
    </LaunchAction>
    <ProfileAction
       buildConfiguration = "Release"