Fix theme switching exception

[HoussemNasri]

Remove installCss(dialogScene) from dialogs because JavaFX already handle that

• If we update dialog stylesheet ourselves then we're breaking the binding made by JavaFX and thus unexpected behaviors may/will happen

Exception

java.lang.IndexOutOfBoundsException: toIndex = 3
	at java.base/java.util.AbstractList.subListRangeCheck(AbstractList.java:507)
	at java.base/java.util.AbstractList.subList(AbstractList.java:497)
	at javafx.base@18/javafx.collections.ModifiableObservableListBase.subList(ModifiableObservableListBase.java:196)
	at javafx.base@18/com.sun.javafx.binding.ContentBinding$ListContentBinding.onChanged(ContentBinding.java:114)
	at javafx.base@18/com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(ListListenerHelper.java:329)
	at javafx.base@18/com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
	at javafx.base@18/javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:239)
	at javafx.base@18/javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
	at javafx.base@18/javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
	at javafx.base@18/javafx.collections.ObservableListBase.endChange(ObservableListBase.java:211)
	at javafx.base@18/javafx.collections.ModifiableObservableListBase.setAll(ModifiableObservableListBase.java:98)
	at org.jabref@100.0.0/org.jabref.gui.theme.ThemeManager.updateAdditionalCss(ThemeManager.java:161)
	at java.base/java.lang.Iterable.forEach(Iterable.java:75)
	at java.base/java.util.Collections$SetFromMap.forEach(Collections.java:5700)
	at org.jabref@100.0.0/org.jabref.gui.theme.ThemeManager.lambda$additionalCssLiveUpdate$10(ThemeManager.java:138)
	at org.jabref@100.0.0/org.jabref.gui.theme.ThemeManager.lambda$additionalCssLiveUpdate$11(ThemeManager.java:137)
	at javafx.graphics@18/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
	at javafx.graphics@18/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
	at javafx.graphics@18/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
	at javafx.graphics@18/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
	at javafx.graphics@18/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:184)
	at java.base/java.lang.Thread.run(Thread.java:833)

• Change in CHANGELOG.md described in a way that is understandable for the average user (if applicable)
• Tests created for changes (if applicable)
• Manually tested changed features in running JabRef (always required)
• Screenshots added in PR description (for UI changes)
• Checked developer's documentation: Is the information available and up to date? If not, I outlined it in this pull request.
• Checked documentation: Is the information available and up to date? If not, I created an issue at https://github.com/JabRef/user-documentation/issues or, even better, I submitted a pull request to the documentation repository.

[Siedlerchr]

Yeah, works fine!