Fix: Thymeleaf syntax (/*[[...]]*/) (#2659)

# Description

Please provide a summary of the changes, including relevant motivation
and context.

Closes #(issue_number)

## Checklist

- [x] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [x] I have performed a self-review of my own code
- [ ] I have attached images of the change if it is UI based
- [ ] I have commented my code, particularly in hard-to-understand areas
- [ ] If my code has heavily changed functionality I have updated
relevant docs on [Stirling-PDFs doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
- [x] My changes generate no new warnings
- [ ] 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)

src/main/resources/templates/security/validate-signature.html

@@ -21,9 +21,9 @@
                   <div th:replace="~{fragments/common :: fileSelector(name='fileInput', multipleInputsForSingleRequest=false, remoteCall='false', accept='application/pdf')}"></div>
                 </div>
                 <div class="mb-3">
-		          <label th:text="#{validateSignature.selectCustomCert}" ></label>
-		          <div th:replace="~{fragments/common :: fileSelector(name='certFile', multipleInputsForSingleRequest=false, notRequired=true, remoteCall='false', accept='.cer,.crt,.pem')}"></div>
-		        </div>
+              <label th:text="#{validateSignature.selectCustomCert}" ></label>
+              <div th:replace="~{fragments/common :: fileSelector(name='certFile', multipleInputsForSingleRequest=false, notRequired=true, remoteCall='false', accept='.cer,.crt,.pem')}"></div>
+            </div>
                 <div class="mb-3 text-left">
                   <button type="submit" id="submitBtn" class="btn btn-primary" th:text="#{validateSignature.submit}"></button>
                 </div>