fix(tooltip): fixed closing on hover from arrow direction

It just restores styles that were removed when migrating to Bootstrap 5 for an unknown reason.

Fixes #3997

src/tooltip/tooltip.scss

@@ -0,0 +1,8 @@
+ngb-tooltip-window {
+	pointer-events: none;
+	position: absolute;
+
+	.tooltip-inner {
+		pointer-events: auto;
+	}
+}

src/tooltip/tooltip.ts

@@ -45,8 +45,8 @@ let nextId = 0;
 		'[class.fade]': 'animation',
 		role: 'tooltip',
 		'[id]': 'id',
-		style: 'position: absolute;',
 	},
+	styleUrls: ['./tooltip.scss'],
 	template: `<div class="tooltip-arrow" data-popper-arrow></div
 		><div class="tooltip-inner"><ng-content></ng-content></div>`,
 })