fix: null value exception handling

Author: vcnainala

resources/js/Pages/Welcome.vue

@@ -63,7 +63,7 @@
                             
                         </div> -->
                             <div
-                                v-if="$page.props.auth.user.first_name != null"
+                                v-if="$page.props.auth.user && $page.props.auth.user.first_name != null"
                                 class="hidden md:flex items-center justify-end md:flex-1 lg:w-0"
                             >
                                 <Link
@@ -249,19 +249,15 @@
                                         mode="button"
                                         ref="structure-search"
                                     ></StructureSearch>
-                                    <a
-                                        class="group inline-flex ring-1 items-center justify-center rounded-full py-2 px-4 focus:outline-none ring-slate-200 text-slate-700 hover:text-slate-900 hover:ring-slate-300 active:bg-slate-100 active:text-slate-600 focus-visible:outline-blue-600 focus-visible:ring-slate-300"
+                                     <Link
+                                        href="/register"
+                                        class="group inline-flex ring-1 items-center justify-center rounded-full py-2 px-4 focus:outline-none ring-slate-200 text-slate-700 hover:text-slate-900 hover:ring-slate-300 active:bg-slate-100 active:text-slate-600 focus-visible:outline-blue-600 focus-visible:ring-slate-300 bg-white"
                                         variant="outline"
                                         color="slate"
-                                        href="/register"
                                         ><span class="ml-3">Submit data</span>
                                         <ToolTip
                                             text="To submit data you will need an account with nmrXiv, so you will be redirected to our register page and once registered you can then go ahead and submit data. For more information please checkout our <a target='_blank' href='//docs.nmrxiv.org' class='text-gray-400' target='_blank'>documentation</a>."
                                         ></ToolTip>
-                                    </a>
-                                    <Link
-                                        class="items-center justify-center px-4 py-3 text-base font-medium rounded-md text-teal-700 sm:px-8"
-                                    >
                                     </Link>
                                 </div>
                             </div>