MultiSelect: Pre-selected disabled options are deselected by filterting and clicking toggleAll (deselect)

[thaihacong]

Describe the bug

Given a multiSelect component with 2 pre-selected disabled options as in https://stackblitz.com/edit/qbuqgb?file=src%2Fapp%2Fdemo%2Fmulti-select-filter-demo.ts.

When a user checks toggleAll checkbox, all options are selected. -> expected

When the user unchecks toggleAll checkbox, non-disabled options are deselected, the 2 pre-selected disabled options are still selected. -> expected

If the user enters a keyword (which does not match some of the pre-selected disabled options) to filter,

and checks toggleAll checkbox

then clear the search keyword, the 2 pre-selected disabled options are now deselected. -> unexpected

The bug seems to be introduced in PrimeNG v17.
It did not happen in old PrimeNG v15.4.1.

Environment

https://stackblitz.com/edit/qbuqgb?file=package.json
"primeng": "17.12.0",
"@angular/cdk": "^17.3.1",

Reproducer

https://stackblitz.com/edit/qbuqgb?file=src%2Fapp%2Fdemo%2Fmulti-select-filter-demo.ts

Angular version

17.3.1

PrimeNG version

17.12.0

Build / Runtime

Angular CLI App

Language

TypeScript

Node version (for AoT issues node --version)

18.18.0

Browser(s)

Firefox. Edge

Steps to reproduce the behavior

No response

Expected behavior

Pre-selected disabled options are selected when filtering and checking toggleAll checkbox.

[thaihacong]

Related to #14617