ci: properly pass NPM auth token secret to script (microsoft#2434)

## Summary:

I noticed NPM publish failing still. My guess is the second addition of
this line to our `.npmrc` is messing it up

## Test Plan:

Testing on 0.78 release.

Author: Saadnajmi

.ado/templates/npm-publish-steps.yml

@@ -26,18 +26,15 @@ steps:
 
   - script: |
       git switch $(Build.SourceBranchName)
-      echo "//registry.npmjs.org/:_authToken=$(NODE_AUTH_TOKEN)" > ~/.npmrc
       yarn nx release --skip-publish --verbose
     env:
       GITHUB_TOKEN: $(githubAuthToken)
     displayName: Version Packages and Github Release
     condition: and(succeeded(), eq(variables['publish_react_native_macos'], '1'))
 
   - script: |
-      echo "//registry.npmjs.org/:_authToken=$(NODE_AUTH_TOKEN)" > ~/.npmrc
+      echo "//registry.npmjs.org/:_authToken=$(npmAuthToken)" > ~/.npmrc
       yarn nx release publish --excludeTaskDependencies
-    env:
-      NODE_AUTH_TOKEN: $(npmAuthToken)
     displayName: Publish packages
     condition: and(succeeded(), eq(variables['publish_react_native_macos'], '1'))