impr(typing): preventing arrow navigation and text selection of the test input

closes #4671

frontend/src/styles/test.scss

@@ -478,6 +478,7 @@
   z-index: -1;
   cursor: default;
   pointer-events: none;
+  user-select: none !important;
 }
 
 #capsWarning {

frontend/src/ts/controllers/input-controller.ts

@@ -1268,6 +1268,16 @@ $("#wordsInput").on("copy paste", (event) => {
   event.preventDefault();
 });
 
+$("#wordsInput").on("select selectstart", (event) => {
+  event.preventDefault();
+});
+
+$("#wordsInput").on("keydown", (event) => {
+  if (event.key.startsWith("Arrow")) {
+    event.preventDefault();
+  }
+});
+
 // Composing events
 $("#wordsInput").on("compositionstart", () => {
   if (Config.layout !== "default") return;