style: fix styling

lib/mv_web/live/member_live/index.html.heex

@@ -2,20 +2,12 @@
   <.header>
     {gettext("Members")}
     <:actions>
-      <form method="post" action={~p"/members/export.csv"} target="_blank" class="inline">
-        <input type="hidden" name="_csrf_token" value={Plug.CSRFProtection.get_csrf_token()} />
-        <input type="hidden" name="payload" value={@export_payload_json} />
-        <button
-          type="submit"
-          class="btn btn-secondary gap-2"
-          aria-label={gettext("Export members to CSV")}
-        >
-          <.icon name="hero-arrow-down-tray" />
-          {gettext("Export to CSV")} ({if @selected_count == 0,
-            do: gettext("all"),
-            else: @selected_count})
-        </button>
-      </form>
+      <.live_component
+        module={MvWeb.Components.ExportDropdown}
+        id="export-dropdown"
+        export_payload_json={@export_payload_json}
+        selected_count={@selected_count}
+      />
       <.button
         class="secondary"
         id="copy-emails-btn"