Refine regex for ranslations extensions' language lists (#329)

* allow spaces in translations extensions' language lists

* improve regex for language detection

Author: agau4779

firestore-translate-text/extension.yaml

@@ -89,7 +89,7 @@ params:
       For these codes, visit the [supported languages list](https://cloud.google.com/translate/docs/languages).
     default: en,es,de,fr
     example: en,es,de,fr
-    validationRegex: "^[a-zA-Z,-]+$"
+    validationRegex: "^[a-zA-Z,-]+[a-zA-Z-]{2,}$"
     validationErrorMessage:
       Languages must be a comma-separated list of ISO-639-1 language codes.
     required: true

rtdb-translate-text/extension.yaml

@@ -96,7 +96,7 @@ params:
       list](https://cloud.google.com/translate/docs/languages).
     default: en,es,de,fr
     example: en,es,de,fr
-    validationRegex: "^[a-zA-Z,-]+$"
+    validationRegex: "^[a-zA-Z,-]+[a-zA-Z-]{2,}$"
     validationErrorMessage:
       Languages must be a comma-separated list of ISO-639-1 language codes.
     required: true