Fix set up encryption toast to use "set up" as action

This changes the "set up encryption" toast to use "set up" as the primary action
button, instead of "upgrade". Other toasts that do use text about upgrading will
keep their primary action text of "upgrade" as before.

Fixes https://github.com/vector-im/riot-web/issues/13231

src/components/views/toasts/SetupEncryptionToast.js

@@ -90,6 +90,7 @@ export default class SetupEncryptionToast extends React.PureComponent {
     getSetupCaption() {
         switch (this.props.kind) {
             case 'set_up_encryption':
+                return _t('Set up');
             case 'upgrade_encryption':
             case 'upgrade_ssss':
                 return _t('Upgrade');

src/i18n/strings/en_EN.json

@@ -558,6 +558,7 @@
     "Verify yourself & others to keep your chats safe": "Verify yourself & others to keep your chats safe",
     "Other users may not trust it": "Other users may not trust it",
     "Update your secure storage": "Update your secure storage",
+    "Set up": "Set up",
     "Upgrade": "Upgrade",
     "Verify": "Verify",
     "Later": "Later",
@@ -2225,7 +2226,6 @@
     "Unable to create key backup": "Unable to create key backup",
     "Without setting up Secure Message Recovery, you'll lose your secure message history when you log out.": "Without setting up Secure Message Recovery, you'll lose your secure message history when you log out.",
     "If you don't want to set this up now, you can later in Settings.": "If you don't want to set this up now, you can later in Settings.",
-    "Set up": "Set up",
     "Don't ask again": "Don't ask again",
     "New Recovery Method": "New Recovery Method",
     "A new recovery passphrase and key for Secure Messages have been detected.": "A new recovery passphrase and key for Secure Messages have been detected.",