Fix bug on nav management

[kattylucy]

if currentPrice is undefined, it's showing as NaN causing error to view page

• Dev

[github-actions]

PR deployed in Google Cloud
URL: https://app-pr2463.k-f.dev
Commit #: 682f840
To access the functions directly check the corresponding deploy Action

[github-actions]

PR deployed in Google Cloud
URL: https://pr2463-app-ff-production.k-f.dev
Commit #: 682f840
To access the functions directly check the corresponding deploy Action