Crash when changing Button Icon

[denny99]

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Plunkr Case (Bug Reports)
https://stackblitz.com/edit/github-5mkgtv?file=src/app/app.component.html

Current behavior
Using a button that has no icon initially fails as the Dom Element won't be generated but is tried to be update when chaning the icon on the fly.

Expected behavior
Buttons without any icon can get a new icon after rendering

What is the motivation / use case for changing the behavior?
In our use case, we wrapped the primeng buttons, disable them on click and show a progress spinner to avoid double clicks.

• Angular version: 11.X

• PrimeNG version: 11.3.1

• Browser: [all]

• Language: [TypeScript 4.2]

[yigitfindikli]

Fixed in b037db9