[Excel] Release ExcelApi 1.19 to GA (#5171)

Author: alison-mk

.openpublishing.publish.config.json

@@ -28,6 +28,7 @@
         "excel-js-1.16",
         "excel-js-1.17",
         "excel-js-1.18",
+        "excel-js-1.19",
         "excel-js-online",
         "onenote-js-1.1",
         "outlook-js-preview",