Fix: Prevent terminal find highlight from overwriting clipboard for CopyOnSelection (#272894)

[vidmt]

This fixes issue #272894 where the terminal's copyOnSelection feature would unintentionally select matches from command-f search and overwrite the clipboard when the find widget highlights search results. Previously, programmatic selections caused by search highlights were treated the same as user selections, triggering the copy-on-selection behavior.

How it fixes the issue

• I added a guard in TerminalClipboardContribution to detect when the FindWidget is active.
• When find triggers and highlights most recent match, CopyOnSelection is blocked from copying
• This prevents copying to clipboard if the selection originates from the find widget rather than a user action.

How to test

1. Open the terminal in VS Code.
2. Ensure terminal.integrated.copyOnSelection is enabled.
3. Open the find widget and search for a term in the terminal.
4. Verify that interacting with the terminal (typing, pasting) does not overwrite your system clipboard with the search highlight.
5. Make a normal selection in the terminal; the copy-on-selection behavior should still work as expected.

[vidmt]

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[vidmt]

BugFix.mov

Here's a video demonstrating the original bug and the fix I made. This fixes the original bug while also maintaining the intended behavior of allowing the user's selections to be copied when the find widget is open.