tests(guifont): delay to stabilize broken guifont test on nightly

Author: glacambre

tests/_common.ts

@@ -397,6 +397,7 @@ ${backup}
                 `);
         await reloadNeovim(server, driver);
         let [input, span] = await createFirenvimFor(server, driver, By.id("content-input"));
+        await driver.sleep(500);
         await sendKeys(driver, "100aa".split("")
                 .concat(webdriver.Key.ESCAPE)
                 .concat("^gjib".split(""))