Add nest translation string for already_in_progress (#139727)

Author: allenporter

homeassistant/components/nest/strings.json

@@ -58,6 +58,7 @@
     },
     "abort": {
       "already_configured": "[%key:common::config_flow::abort::already_configured_account%]",
+      "already_in_progress": "[%key:common::config_flow::abort::already_in_progress%]",
       "missing_configuration": "[%key:common::config_flow::abort::oauth2_missing_configuration%]",
       "missing_credentials": "[%key:common::config_flow::abort::oauth2_missing_credentials%]",
       "authorize_url_timeout": "[%key:common::config_flow::abort::oauth2_authorize_url_timeout%]",