Put PTT behind 'feature flag'

AKA does the URL hash start with '#ptt'

This will let us merge PTT back to the main branch

.vscode/settings.json

@@ -1,5 +1,5 @@
 {
-  "editor.formatOnSave": true,
+  "editor.formatOnSave": false,
   "editor.insertSpaces": true,
   "editor.tabSize": 2
-}
+}

src/home/RegisteredView.jsx

@@ -13,6 +13,7 @@ import { JoinExistingCallModal } from "./JoinExistingCallModal";
 import { useHistory } from "react-router-dom";
 import { Headline, Title } from "../typography/Typography";
 import { Form } from "../form/Form";
+import { shouldShowPtt } from "../shouldShowPtt";
 
 export function RegisteredView({ client }) {
   const [loading, setLoading] = useState(false);
@@ -98,14 +99,14 @@ export function RegisteredView({ client }) {
                 {loading ? "Loading..." : "Go"}
               </Button>
             </FieldRow>
-            <FieldRow className={styles.fieldRow}>
+            {shouldShowPtt() && <FieldRow className={styles.fieldRow}>
               <InputField
                 id="ptt"
                 name="ptt"
                 label="Push to Talk"
                 type="checkbox"
               />
-            </FieldRow>
+            </FieldRow>}
             {error && (
               <FieldRow className={styles.fieldRow}>
                 <ErrorMessage>{error.message}</ErrorMessage>

src/home/UnauthenticatedView.jsx

@@ -15,6 +15,7 @@ import { Form } from "../form/Form";
 import styles from "./UnauthenticatedView.module.css";
 import commonStyles from "./common.module.css";
 import { generateRandomName } from "../auth/generateRandomName";
+import { shouldShowPtt } from "../shouldShowPtt";
 
 export function UnauthenticatedView() {
   const [loading, setLoading] = useState(false);
@@ -112,14 +113,14 @@ export function UnauthenticatedView() {
                 autoComplete="off"
               />
             </FieldRow>
-            <FieldRow>
+            {shouldShowPtt() && <FieldRow>
               <InputField
                 id="ptt"
                 name="ptt"
                 label="Push to Talk"
                 type="checkbox"
               />
-            </FieldRow>
+            </FieldRow>}
             <Caption>
               By clicking "Go", you agree to our{" "}
               <Link href={privacyPolicyUrl}>Terms and conditions</Link>