fix(datatable): fix filter overlay closing when interacting with nested overlay components

[VaishnaviD5900]

Description

When using components like MultiSelect, Select, or TreeSelect as custom
filters inside a DataTable column, the filter overlay panel closed
immediately upon interacting with any option.

Root Cause

The isOutsideClicked method in ColumnFilter only checked if the
clicked target was inside this.overlay. However, nested overlay panels
(like MultiSelect dropdown) are appended to the body by default, so they
exist outside this.overlay in the DOM, causing them to be incorrectly
treated as outside clicks.

Additionally, the overlayEventListener had a condition that prevented
selfClick from being set correctly for nested overlays.

Fix

• Simplified overlayEventListener to always set selfClick = true
  when any overlay-click event is received
• Updated isOutsideClicked to check if the target is inside any active
  overlay panel using closest('[data-pc-section="panel"], [data-pc-section="overlay"]')

How to Test

1. Go to /datatable/#advanced_filter
2. Click the filter icon on the "Agent" column
3. Click any option in the MultiSelect, checkbox should toggle and
   panel should stay open
4. Also verify clicking outside still correctly closes the panel

Closes

Closes #8537
Closes #8213