Clearly no, if you dont want to, you can leave it empty. If you leave it empty it license agreement dialog will not be shown. Here is a screenshoot how it would look like if you have a license agreement.
License agreement is compiled into your installer, this means once your client has an installer with current license, you will need to generate new installer if you want to update your license agreement. That is the reason why we recommend you to have a license agreement which is generous and covers all kind of gaps for your needs.
Once enabled users cannot install your product unless licence agreement has been accepted.
If you have a license agreement but dont want to remove it in order to generate a new installer without license agreement, you can uncheck “Include License Agreement” Settings under “Build”->”Settings” tab. This will simply skip license check despite having License Agreement content.