Account: increase button width on account landing page

[KFie]

Environment: mobile

Reproduce:

1. Log in
2. Go to account landing page

Issue: note the button label "Payment settings" doesn't fit but there actually is no need for an ellipsis. Since there is enough space, I recommend to increase the button width so the label can fully display. Also see #192.

[freddyka]

Issue not fixed for poster v2.1.

-->reason is that mobile menu button can't be used (see#199)