Rename TEST_MODE to specific variable for CodeQL Action

This allows us to set it automatically in the workflow generator,
simplifying things and reducing the scope for error.

.github/workflows/__test-proxy.yml

@@ -42,14 +42,11 @@ jobs:
       with:
         languages: javascript
         tools: ${{ steps.prepare-test.outputs.tools-url }}
-      env:
-        TEST_MODE: true
     - uses: ./../action/analyze
-      env:
-        TEST_MODE: true
     env:
       https_proxy: http://squid-proxy:3128
       INTERNAL_CODEQL_ACTION_DEBUG_LOC: true
+      CODEQL_ACTION_TEST_MODE: true
     container:
       image: ubuntu:22.04
       options: --dns 127.0.0.1