Update add-watermark.html (#1893)

shifted add watermark submit button to left

src/main/resources/templates/security/add-watermark.html

@@ -108,7 +108,7 @@
                   <input type="checkbox" id="convertPDFToImage" name="convertPDFToImage">
                   <label for="convertPDFToImage" th:text="#{watermark.selectText.10}"></label>
                 </div>
-                <div class="mb-3 text-center">
+                <div class="mb-3 text-left">
                   <input type="submit" id="submitBtn" th:value="#{watermark.submit}" class="btn btn-primary">
                 </div>
               </form>
@@ -144,4 +144,4 @@
       <th:block th:insert="~{fragments/footer.html :: footer}"></th:block>
     </div>
   </body>
-</html>
+</html>