Remove gridlines from balance history mini-chart

On the user's profile page, let us remove the background gridlines from the balance history mini-chart

added To Do label

assigned to @delrifai

added Doing label

removed To Do label

mentioned in commit 2429990e

@mcfarhat I will also increase the stroke width so that all graphs become aligned with the new hive price chart

mentioned in commit 04e1d0c0

mentioned in merge request !601 (merged)

assigned to @mcfarhat and unassigned @delrifai

added Review label

removed Doing label

closed