InfoBanner title always renders as `span` tag

[nlopin]

When using the InfoBanner component, it is impossible to set the HTML-tag for the message's title. It always uses <span>, which can be incorrect.

What was expected to happen?

• we should use a headline tag (h3 or similar) by default
• user can set the level of the tag

[JanHamara]

Hey, so I've changed it to <Headline> in the above MR

[nlopin]

@JanHamara we should allow picking the level because we don't know the application use case