Move Low Bandwidth feature to devtools. (#32797)

* Move and rename low bandwidth mode.

* Still in use.

* remove string

* Add a test for low bandwidth mode

* Test requests too

* update snaps

* New year!

apps/web/test/unit-tests/components/views/settings/tabs/user/LabsUserSettingsTab-test.tsx

@@ -48,6 +48,6 @@ describe("<LabsUserSettingsTab />", () => {
         // non-beta labs section
         expect(screen.getByText("Early previews")).toBeInTheDocument();
         const labsSections = container.getElementsByClassName("mx_SettingsSubsection");
-        expect(labsSections).toHaveLength(9);
+        expect(labsSections).toHaveLength(8);
     });
 });