Fixed the default "dark" theme for button component.

There was a bug when sometimes the single value for the select component was not working properly, as the value attribute was not added to the sl-select element in HTML. I added a fix so that the value attributes are added with JS for both single select and multiple select.

There was a bug with some attributes on the carousel component. It should be fixed now.

There was a small bug when a user does not provide a close button, causing an error in the function. The close button is optional, so now this is fixed with the updated function.

Just before the page loads, there was a brief flash of unstyled HTML. This is now fixed, and the component is visible once it is ready.