Fix empty string comparison issues in the codebase (#16686)

Automatic Merge

app/file.go

@@ -498,7 +498,7 @@ func (a *App) UploadMultipartFiles(teamId string, channelId string, userId strin
 // the same length. clientIds should either not be provided or have the same length as files and filenames.
 // The provided files should be closed by the caller so that they are not leaked.
 func (a *App) UploadFiles(teamId string, channelId string, userId string, files []io.ReadCloser, filenames []string, clientIds []string, now time.Time) (*model.FileUploadResponse, *model.AppError) {
-	if len(*a.Config().FileSettings.DriverName) == 0 {
+	if *a.Config().FileSettings.DriverName == "" {
 		return nil, model.NewAppError("UploadFiles", "api.file.upload_file.storage.app_error", nil, "", http.StatusNotImplemented)
 	}
 
@@ -703,7 +703,7 @@ func (a *App) UploadFileX(channelId, name string, input io.Reader,
 		o(t)
 	}
 
-	if len(*a.Config().FileSettings.DriverName) == 0 {
+	if *a.Config().FileSettings.DriverName == "" {
 		return nil, t.newAppError("api.file.upload_file.storage.app_error",
 			"", http.StatusNotImplemented)
 	}