Add prop to hide the close button (X) on BBBHint

[Arthurk12]

Is your feature request related to a problem? Please describe.
In some use cases, the close button (X) on BBBHint does not make sense — for example, informational hints that should only be dismissed by interacting with another UI element, or tooltip-style hints with no explicit dismiss action. There is currently no way to hide this button.

Describe the solution you'd like
Add a boolean prop (e.g. hideCloseButton) to BBBHint that, when true, hides the X button from the component.

Affected component(s)
BBBHint

Proposed API / Usage Example

// Hint without a close button
<BBBHint hideCloseButton content="This hint cannot be manually dismissed.">
  <BBBButton>Info</BBBButton>
</BBBHint>