Remove unused vulnerable dependency "xlsx"

[mtrefzer]

Describe the bug

The dependency "xlsx" is vulnerable and not used in the project, therefor it should be removed.

Pull Request Link

#17548

Reason for not contributing a PR

• Lack of time
• Unsure how to implement the fix/feature
• Difficulty understanding the codebase
• Other

Other Reason

No response

Reproducer

#17548

Environment

Ubuntu 24
node 22

Angular version

19

PrimeNG version

v19

Node version

22

Browser(s)

No response

Steps to reproduce the behavior

package.json contains "xlsx"

Expected behavior

package.json should not contain "xlsx"

[FranSalRod]

Hi!
If you have xlsx in your package.json is becouse you put it yourself. Primeng do not install xlsx.
If your project dont need it, and is vulnerable, just remove it.

[mtrefzer]

It's a dependency in apps/showcase/package.json.