chore: only run release-notes if BUMP_CANDIDATE is false (#16956)

The release-notes script generates a RELEASE_NOTES file based on the current
version and current changelog. During a BUMP_CANDIDATE build, a new version
number has been generated, but no corresponding changelog has been
created/updated. This causes the release notes to fail (and currently breaks the
pipeline).

Simplest fix is to skip release notes generation for these builds.


----

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build.sh

@@ -94,6 +94,10 @@ if [ "$check_compat" == "true" ]; then
 fi
 
 # Create the release notes for the current version. These are ephemeral and not saved in source.
-node ./scripts/create-release-notes.js
+# Skip this step for a "bump candidate" build, where a new, fake version number has been created
+# without any corresponding changelog entries.
+if ! ${BUMP_CANDIDATE:-false}; then
+    node ./scripts/create-release-notes.js
+fi
 
 touch $BUILD_INDICATOR