fix(style): Fix input element zoom issues on iOS.
fix(style): Fix input element zoom issues on iOS.

Set input element font-size to 16px.

mozilla/fxa-content-server,mozilla/fxa-content-server,shane-tomlinson/fxa-content-server,shane-tomlinson/fxa-content-server,mozilla/fxa-content-server,shane-tomlinson/fxa-content-server