ci: update workflows to use Node 20.x instead of 22.x

Node 22.17.0 has a critical bug with ES Module loading in worker threads
that causes 'Cannot read properties of undefined (reading getStatus)' errors.
This affects run-workers command when using ES modules.

Node 20.x LTS does not have this issue and is recommended for production use.

Changed both unit-tests and runner-tests jobs in test.yml workflow.

Author: kobenguyent

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [22.x]
+        node-version: [20.x]
 
     steps:
       - uses: actions/checkout@v5
@@ -47,7 +47,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [22.x]
+        node-version: [20.x]
 
     steps:
       - uses: actions/checkout@v5