Moving the cursor manually doesn't cancel search

Describe the bug
This is basically a complete duplicate of https://github.com/syl20bnr/spacemacs/issues/10410. To reproduce:

• Search sth with '/'.
• Without pressing 'RET' click on the main buffer.
• The vim functionality is now broken (e.g., try selecting text with the mouse and press d.)

Expected behavior
The search should be canceled when the user manually moves the cursor.

Environment (please complete the following information):

- Extension (VsCodeVim) version: 1.16
Version: 1.49.0-insider
Commit: bd08768fd310d34cdd4423a53e5f3ca77340fea5
Date: 2020-08-14T06:47:57.598Z (2 days ago)
Electron: 9.2.0
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Darwin x64 19.0.0
- Issue Type: `Bug`
- Extension Name: `vim`
- Extension Version: `1.16.0`
- OS Version: `Darwin x64 19.0.0`
- VSCode version: `1.49.0-insider`

{
	"messages": [],
	"activationTimes": {
		"codeLoadingTime": 138,
		"activateCallTime": 2,
		"activateResolvedTime": 3,
		"activationReason": {
			"startup": true,
			"extensionId": {
				"value": "vscodevim.vim",
				"_lower": "vscodevim.vim"
			},
			"activationEvent": "*"
		}
	},
	"runtimeErrors": []
}

Reproduce the issue by starting a search with /, clicking the main buffer before pressing RET, and checking whether Vim behavior remains broken. Trace the search-cancellation and mouse-cursor handling entry points; done means manual cursor movement cancels the search and mouse selection followed by d works.