fix: missing bot name in orchestrate (#20747)

web/app/components/base/chat/chat/index.tsx

             {
               !noChatInput && (
                 <ChatInputArea
-                  botName={appData?.site.title || ''}
+                  botName={appData?.site.title || 'Bot'}
                   disabled={inputDisabled}
                   showFeatureBar={showFeatureBar}
                   showFileUpload={showFileUpload}