feat(ui): configure planning horizon alongside leave balances

src/app/components/user-settings/user-settings.scss

@@ -20,26 +20,3 @@ mat-dialog-content > p {
 mat-form-field {
 	width: 100%;
 }
-
-.planning-dates {
-	min-width: 0;
-	margin: 0 0 1rem;
-	padding: 0;
-	border: 0;
-
-	legend {
-		font-weight: 600;
-	}
-
-	p {
-		margin: 0.5rem 0 1rem;
-		color: var(--ui-text-secondary);
-	}
-
-	.validation-error {
-		color: var(--ui-error-text);
-		background: var(--ui-error-bg);
-		padding: 0.75rem;
-		border-radius: 0.5rem;
-	}
-}