Dropdown: Floating placeholder overlapping when value is null or undefined.

[Elias-Graf]

Describe the bug

Let's say you have a dropdown with the following options:

  options: { label: string; value: number | undefined }[] = [
    { label: 'None', value: undefined },
    { label: 'First', value: 0 },
    { label: 'Second', value: 1 },
  ];

If you have a floating label and select the None value, the floating label will overlap with the value like this:

Most likely this is because of this check, that is comparing if the value is something, instead of checking if an option is selected:
https://github.com/primefaces/primeng/blob/ae58a4948ac6225e053641e7462a5f787be28e48/src/app/components/dropdown/dropdown.ts#L1012C1-L1015C8

Most likely the issue would be solved, if the same code is used as for:
https://github.com/primefaces/primeng/blob/ae58a4948ac6225e053641e7462a5f787be28e48/src/app/components/dropdown/dropdown.ts#L1002C1-L1010C8

Environment

Not applicable, otherwise please let me know.

Reproducer

https://stackblitz.com/edit/github-epdzxk?file=src%2Fapp%2Fapp.component.html

Angular version

17.x.x

PrimeNG version

^17.18.10

Build / Runtime

Angular CLI App

Language

TypeScript

Node version (for AoT issues node --version)

v18.20.3

Browser(s)

Firefox, Chrome

Steps to reproduce the behavior

1. Open provided reproducer
2. Select none from the dropdown

Expected behavior

Label should be floating when an option is selected. It should only not be floating, if the current selected value is not an option, e.g.: no option is selected.