Do not expect nil returned by upload()

Author: lfkellogg

lib/fastlane/plugin/firebase_app_distribution/actions/firebase_app_distribution_action.rb

@@ -34,11 +34,7 @@ def self.run(params)
         app_view = binary_type == :AAB ? 'FULL' : 'BASIC'
         app = fad_api_client.get_app(app_id, app_view)
         validate_app!(app, binary_type)
-
         release_id = fad_api_client.upload(app.project_number, app_id, binary_path, platform.to_s)
-        if release_id.nil?
-          return
-        end
 
         if binary_type == :AAB && app.aab_certificate.empty?
           updated_app = fad_api_client.get_app(app_id)

lib/fastlane/plugin/firebase_app_distribution/client/firebase_app_distribution_api_client.rb

@@ -127,10 +127,10 @@ def upload_binary(app_id, binary_path, platform)
       #   app_id - Firebase app ID
       #   binary_path - Absolute path to your app's aab/apk/ipa file
       #
-      # Returns the release_id on a successful release, otherwise returns nil.
+      # Returns the release_id of the uploaded release.
       #
-      # Throws a UI error if the number of polling retries exceeds MAX_POLLING_RETRIES
-      # Crashes if not able to upload the binary
+      # Crashes if the number of polling retries exceeds MAX_POLLING_RETRIES or if the binary cannot
+      # be uploaded.
       def upload(project_number, app_id, binary_path, platform)
         binary_type = binary_type_from_path(binary_path)