Chat: don't add selection to chat on option+l shortcut (#5310)

Previously, the option+l shortcut triggered two commands:

- Toggle chat
- Add selection to chat

This was problematic because the selection is already an initial context
in chat so the chat input ended up having duplicate chips (one "initial"
    and one "user").

This PR fixes the problem by removing the option+l shortcut for "Add
selection to chat" so that it only toggles the visibility of the
sidebar. Users can still manually add the selection to the chat input
with the option+/ shortcut.

## Test plan

* Local build
* Select text
* Trigger option+l multiple times
* Confirm that it doesn't keep adding the selection to the chat
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## Changelog

* Fix bug where continuously triggering alt+l (option+l for macOS) would
add duplicate context items to the chat input. Use the alt+/ shortcut to
explicitly add the selection to the chat input.
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vscode/package.json

@@ -647,11 +647,6 @@
         "key": "alt+/",
         "when": "cody.activated && editorTextFocus && editorHasSelection"
       },
-      {
-        "command": "cody.mention.selection",
-        "key": "alt+l",
-        "when": "cody.activated && editorTextFocus && editorHasSelection"
-      },
       {
         "command": "cody.tutorial.chat",
         "key": "alt+l",

vscode/test/e2e/chat-keyboard-shortcuts.test.ts

@@ -26,6 +26,6 @@ test('chat keyboard shortcuts for sidebar chat', async ({ page, sidebar }) => {
 
     // Alt+L with a selection opens a new chat (with selection mention).
     await selectLineRangeInEditorTab(page, 3, 5)
-    await page.keyboard.press('Alt+L')
+    await page.keyboard.press('Alt+/')
     await expect(chatSidebarInput).toContainText('buzz.ts buzz.ts:3-5 ')
 })