fix(modal): fix focusing out of modal when elements inside modal are clicked

[driskull]

Related Issue: #6579

Summary

• Adds optional private property focusTrapContentEl to the FocusTrapComponent which prevents clicked child elements from deactivating the focus trap.
  • If this property isn't defined on the FocusTrapComponent the host element will be used.
• Anytime an element is clicked, it runs to check if the element is within the focusTrapContentEl and will prevent focus trap from being disabled if true.
• Adds CSS pointer-events none to content within button for preventing pointer event on it.