web: Fix nonsensical use of TypeScript Omit<>.

Omit<…, "undefined"> removes the "undefined" key from an object.  The
intention was clearly Exclude<…, undefined> which removes undefined
from a union, or NonNullable<…> which removes both undefined and null.
However, it’s simpler here to provide the expected type directly.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

web/src/dialog_widget.ts

@@ -259,7 +259,7 @@ export function launch(conf: DialogWidgetConfig): string {
 export function submit_api_request(
     request_method: AjaxRequestHandler,
     url: string,
-    data: Omit<Parameters<AjaxRequestHandler>[0]["data"], "undefined">,
+    data: Record<string, unknown>,
     {
         failure_msg_html = $t_html({defaultMessage: "Failed"}),
         success_continuation,

web/src/settings_ui.ts

@@ -35,7 +35,7 @@ export const strings = {
 export function do_settings_change(
     request_method: AjaxRequestHandler,
     url: string,
-    data: Omit<Parameters<AjaxRequestHandler>[0]["data"], "undefined">,
+    data: Record<string, unknown>,
     $status_element: JQuery,
     {
         success_msg_html = strings.success_html,