Fixed firefox compatibility and added missing icons to feature pages (#2863)

# Description of Changes

Fixed icon incompatibility with firefox
Added missing icons to feature pages

Closes #(2833)


![image](https://github.com/user-attachments/assets/51ba008a-f6ab-4e29-9a79-99d85d152689)


---

## Checklist

### General

- [ x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ x] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ x] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md)
(if applicable)
- [ x] I have performed a self-review of my own code
- [ x] My changes generate no new warnings

### Documentation

- [ x] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ x] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ x] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ x] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing)
for more details.

Co-authored-by: Reece Browne <reece@stirling.pdf>

src/main/resources/templates/fragments/navbarEntryCustom.html

@@ -1,13 +1,14 @@
 <th:block th:fragment="navbarEntry(endpoint, toolIcon, titleKey, descKey, tagKey, toolGroup)"
-th:if="${@endpointConfiguration.isEndpointEnabled(endpoint)}">
+  th:if="${@endpointConfiguration.isEndpointEnabled(endpoint)}">
   <a th:id="@{${endpoint}}" class="dropdown-item" style="position:relative" th:href="@{${endpoint}}"
     th:data-bs-link="@{${endpoint}}"
     th:classappend="${endpoint.equals(currentPage)} ?  ${toolGroup} + ' active' : '' + ${toolGroup}"
     th:data-bs-tags="#{${tagKey}}" th:data-bs-title='#{${titleKey}}'>
     <div style="height:2.5rem;align-items: center;display: flex" th:title="#{${descKey}}" class="icon" alt="icon"
       th:class="@{${toolGroup}}">
-      <svg class="nav-icon" style="height: 2.7rem; width:2.7rem; align-items:center; display: flex; justify-content: center;">
-        <use th:href="@{${toolIcon}}"></use>
+      <svg class="nav-icon"
+        style="height: 2.7rem; width:2.7rem; align-items:center; display: flex; justify-content: center;">
+        <use th:xlink:href="@{${toolIcon}}"></use>
       </svg>
       <span class="icon-text" th:text="#{${titleKey}}"></span>
     </div>