Temporarily disable Kotlin analysis in PR checks

Kotlin analysis is incompatible with Kotlin 1.8.0, which is now rolling
out to the Actions runner images.

While we work on a more permanent fix to our PR checks, this will
prevent us losing other
test coverage.

.github/workflows/__javascript-source-root.yml

@@ -7,6 +7,7 @@ name: PR Check - Custom source root
 env:
   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
   GO111MODULE: auto
+  CODEQL_EXTRACTOR_JAVA_AGENT_DISABLE_KOTLIN: 'true'
 on:
   push:
     branches: