Replace confirmCloseAllTabs with confirmOnClose

[carlos-zamora]

Summary of the Pull Request

Replaces the warning.confirmCloseAllTabs setting with a warning.confirmOnClose enum setting that accepts the following:

• never: don't present a warning dialog when closing a session
• automatic: present a warning dialog when closing multiple tabs/panes at once
• always: present a warning dialog when closing any session

The confirmation dialog contains a "don't ask me again" checkbox. When checked, we update the setting to never.

This setting also affects the following actions:

• "close other tabs"
• "close tabs after"
• "close other panes"
• "quit"
  The appropriate confirmation dialog is shown in these scenarios. We also present an aggregate dialog instead of prompting the user once per tab/pane. If there are no other tabs/panes, we don't present a dialog and treat the key binding as unhandled (passing the key through).

References and Relevant Issues

Iteration of #19944

Validation Steps Performed

• closing a tab:
  • ✅ 1 pane --> no dialog
  • ✅ 2 panes --> dialog
  • ✅ action and middle clicking tab trigger same flow
• close all other tabs:
  • ✅ no other tabs --> no dialog
  • ✅ 1 other tab --> dialog
• close all other panes:
  • ✅ 1 pane --> no dialog
  • ✅ 2 panes --> dialog
• close all tabs after the current tab:
  • ✅ no tabs after --> no dialog (even if tabs before)
  • ✅ 1 tab after --> dialog
• close window:
  • ✅ 2 tabs --> dialog
  • ✅ 2 panes --> dialog
  • ✅ 1 tab with one pane --> no dialog
• Quit the Terminal:
  • ✅ 3 windows --> dialog
  • ✅1 window --> dialog
• ✅ "don't ask me again" checkbox checked --> setting changed to "never"
• ✅ "never" --> no dialog for scenarios above
• ✅ "always" --> dialog always appears, even when closing a single pane

PR Checklist

Closes #5301
Closes #6641
"don't ask me again" checkbox is also mentioned in #10000

Co-authored by @zadjii-msft

[carlos-zamora]

Demo

Settings UI:

Dialog UI:

Here's all the possible strings for the dialog:

[Hlsgs]

Apologies if this is not the proper place for this question: is it possible to implement a fourth setting that would mean "present a warning dialog when closing multiple tabs/panes at once AND at least one background tab is in Running State"?