[FSSDK-9586] restore node engine to >=14 (#912)

also add back unit test ci for node14

Author: raju-opti

.github/workflows/javascript.yml

@@ -63,7 +63,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: ['16', '18', '20']
+        node: ['14', '16', '18', '20']
     steps:
     - uses: actions/checkout@v3
     - name: Set up Node ${{ matrix.node }}

package.json

@@ -94,7 +94,7 @@
   },
   "license": "Apache-2.0",
   "engines": {
-    "node": ">=16.0.0"
+    "node": ">=14.0.0"
   },
   "keywords": [
     "optimizely"