Invalid error handling on book now

[aidenszeto]

Background

BLOCKED BY #161. Should be done in conjunction with #161.

listingPage.component.js access an undefined attribute when an error occurs on the handleSessionRedirect() function.

To replicate:

• navigate to this listing: http://localhost:3000/listing/6010ad210b57d966ffcfc4dd (make sure you are in your dev environment and switch to the production database).
• select valid reservation dates and hit "book now"

NOTE: This error has only been discovered on error handling related to issue #161. It may exist on other errors as well and should be tested first.

Task

• Replicate error
• Fix alert() to return the proper error message

Done When

• Error messages are alerted at the top of the screen
• Alert does not access undefined field