Null pointer after selecting "Always" on UntrackMe

Description

UntrackMe presents a null pointer exception and does not open the link after selecting Always, then it works with no problem in future cases.

Reproduce error

• Download UntrackMe, Bromite, and App Manager from F-Droid in a clean 12L environment
• Set all links to open in UntrackMe
• Open a few Reddit, Youtube links with UntrackMe but only selecting Just once on Bromite
• Open a Bitly link, but this time select Always
• See error

Stack trace

FATAL EXCEPTION: main
Process: app.fedilab.nitterizeme, PID: 25393
java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.Collection.iterator()' on a null object reference
	at java.util.AbstractCollection.addAll(AbstractCollection.java:343)
	at app.fedilab.nitterizeme.helpers.Utils.union(Utils.java:963)
	at app.fedilab.nitterizeme.activities.AppsPickerActivity.lambda$onCreate$2$AppsPickerActivity(AppsPickerActivity.java:182)
	at app.fedilab.nitterizeme.activities.-$$Lambda$AppsPickerActivity$o_FCqLSBf_P8dDuHUgj24h2JCv0.onClick(Unknown Source:6)
	at android.view.View.performClick(View.java:7455)
	at android.view.View.performClickInternal(View.java:7432)
	at android.view.View.access$3700(View.java:835)
	at android.view.View$PerformClick.run(View.java:28810)
	at android.os.Handler.handleCallback(Handler.java:938)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loopOnce(Looper.java:201)
	at android.os.Looper.loop(Looper.java:288)
	at android.app.ActivityThread.main(ActivityThread.java:7798)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)

Phone Information

Pixel 5a on Android 12 (S2B1.21112.006)

This could be an edge case. If it is don't be afraid to close this issue.