ZCU/Reduce the footer vendor credit to the company name (#1467)

The footer credit read "Theme by" stacked above the company name. Drop the
wording and leave the name on its own.

The i18n key footer.theme.by.message is now unused and removed from
en.json5 and cs.json5. Nothing in the credit is translated any more.

The anchor itself is untouched, so its rendering — including the *ngVar
binding and the [href] — behaves exactly as before.

Refs dataquest-dev/dspace-customers#592

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: MatusBeke

src/assets/i18n/cs.json5

@@ -2174,8 +2174,6 @@
   "footer.link.contact-us": "Kontaktujte nás",
   // "footer.link.university": "University Library",
   "footer.link.university": "Univerzitni Knihovna",
-  // "footer.theme.by.message": "Theme by",
-  "footer.theme.by.message": "Theme by",
   // "forgot-email.form.header": "Forgot Password",
   "forgot-email.form.header": "Zapomenuté heslo",
   // "forgot-email.form.info": "Enter the email address associated with the account.",

src/assets/i18n/en.json5

@@ -1733,8 +1733,6 @@
 
   "footer.link.university": "University Library",
 
-  "footer.theme.by.message": "Theme by",
-
   "forgot-email.form.header": "Forgot Password",
 
   "forgot-email.form.info": "Enter the email address associated with the account.",

src/themes/custom/app/footer/footer.component.html

@@ -93,7 +93,6 @@ <h5 class="text-uppercase">Footer Content</h5>
               </ul>
             </div>
             <div class="footer-sign">
-              <p class="theme-by">{{ 'footer.theme.by.message' | translate }}</p>
               <a class="dtq-sign text-white" *ngVar="(themedByCompanyName$ | async)?.payload?.values[0] as companyName"
                  [href]="(themedByUrl$ | async)?.payload?.values[0]"
                  [title]="companyName">