Improve banner styles

[zoltanszogyenyi]

• [x] I have searched the Issues to see if this bug has already been reported
• [x] I have tested the latest version

I've checked the banner component and I'd like to do the following changes:

• [ ] the X icon should have even paddings (ie. px-2 py-2 or p-2 instead of px-4 py-2)
• [ ] responsiveness issues for some of the banners (marketing cta banner, bottom banner)

The button is too large, we should make it smaller:

The elements should span the whole width of the screen:

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For reference we can check out the banners from the main Flowbite Library.