Fix a bug in Real CV Calculator that happens when reviewing a giveaway

[gizellos]

I got this error when I clicked on Review Giveaway while I was making a new giveaway.

Error in event handler for (unknown): TypeError: Cannot read property 'price_overview' of undefined
    at response (chrome-extension://jcipimoeegokakknfckimajbaddijmig/esgst.js:17811:61)
    at chrome.runtime.sendMessage.response (chrome-extension://jcipimoeegokakknfckimajbaddijmig/esgst.js:36330:21)

[rafaelgomesxyz]

When you clicked on Review Giveaway? Not on Create Giveaway or something else?

[rafaelgomesxyz]

I think I fixed it. Pretty sure it's because you've been loading too much game data and you can't currently make requests to the Steam API.