Fix login page placeholder translations not appearing for select languages

Steps to reproduce:

1. In Studio Modeler > Resources > I18n Files, create the following files:

• messages_it_IT.properties
• messages_ar.properties

2. In each of these files, override the translations for label.login.username, label.login.password, and label.login.logIn; example:

label.login.username=translatedUsername
label.login.password=translatedPassword
label.login.logIn=translatedButton

3. After reloading studio project .jar, relaunch browser after changing display language to Italian and Arabic respectively

4. Observe that the placeholders are not translated for these languages.

Observed in Chrome, Edge, and Firefox browsers.