Fixes webview responding shortcuts twice on linux

[onequid]

Add a platform condition for the registering of the "did-keydown" event listener.
Avoided transfering keydown events on Linux.
This PR fixes #82670

[mjbvz]

Looks reasonable. Let's see if this causes any regression for other comments. Please test using the next insiders build

[mjbvz]

I had to revert this change as it broke keybindings on linux: #85102

Please take another look at the addressing the problem in a different way

[onequid]

I apologize for not testing all the keybindings and the inconvenience brought by it.
And sorry that I have to drop this issue.

Here's something I tried. Surrounding following lines with the !isLinux if-condition would work properly as expected. However, the codes are there for a reason, I tried but failed to figure out what are these lines for. I doubt the change would break something somewhere else.

vscode/src/vs/workbench/electron-browser/window.ts

Lines 160 to 165 in 7521ebd

	// Support runKeybinding event
	ipc.on('vscode:runKeybinding', (event: IpcEvent, request: IRunKeybindingInWindowRequest) => {
	if (document.activeElement) {
	this.keybindingService.dispatchByUserSettingsLabel(request.userSettingsLabel, document.activeElement);
	}
	});

and the ipc event is sent here, but not listened anywhere else beside lines in window.ts mentioned above.

vscode/src/vs/platform/menubar/electron-main/menubar.ts

Lines 738 to 742 in 9c8b2f2

	if (invocation.type === 'commandId') {
	activeWindow.sendWhenReady('vscode:runAction', { id: invocation.commandId, from: 'menu' } as IRunActionInWindowRequest);
	} else {
	activeWindow.sendWhenReady('vscode:runKeybinding', { userSettingsLabel: invocation.userSettingsLabel } as IRunKeybindingInWindowRequest);
	}

[mjbvz]

Just make sure any changes:

• Don't break a normal keybindings for menu items when a webview is open
• Don't break a normal keybindings for menu items when a webview is not opened
• That everything works properly with both "window.titleBarStyle": "custom" and "window.titleBarStyle": "native"