Reconsider label 'Subscribe' button design

In !75961 (merged), the appearance of the labels Subscribe button was improved and aligned with Pajamas guidelines. However, we kept the width of the button at 105px as the buttons would otherwise be horizontally off-center.

The goal of this issue is to look into removing the static width of the Subscribe buttons.

Screenshots

Before	After (105px width, !75961 (merged))	After (unset width, inconsistent)