Update creating-team-manifest-manually-for-webpart.md

stated that the 'dest' parameter must be encodede

Author: lucabandMSFT

docs/spfx/web-parts/guidance/creating-team-manifest-manually-for-webpart.md

@@ -107,6 +107,9 @@ Notice the `componentId` query parameter in the `configurationUrl`. You should n
 
 See more details around the Microsoft Teams manifest options from the [Microsoft Teams developer guidance](https://docs.microsoft.com/microsoftteams/platform/concepts/apps/apps-package).
 
+> [!IMPORTANT]
+> The `dest` query parameter in the `configurationUrl` must be encoded. Non encoded URLs are not supported.
+
 Below json structure demonstrates sample manifest file content.
 
 ```json