change i18n shibboleth label

resources/i18n/en.json5

@@ -458,9 +458,10 @@
   "login.form.forgot-password": "Have you forgotten your password?",
   "login.form.header": "Please log in to DSpace",
   "login.form.new-user": "New user? Click here to register.",
+  "login.form.or-divider": "or",
   "login.form.password": "Password",
   "login.form.submit": "Log in",
-  "login.form.shibboleth": "Shibboleth",
+  "login.form.shibboleth": "Log in with Shibboleth",
   "login.title": "Login",
 
   "logout.form.header": "Log out from DSpace",

src/app/shared/log-in/methods/shibboleth/log-in-shibboleth.component.html

-<a class="btn btn-lg btn-primary btn-block mt-2" [href]="location" role="button">
+<a class="btn btn-lg btn-primary btn-block mt-2 text-white" [href]="location" role="button">
   {{"login.form.shibboleth" | translate}}
 </a>