Setting then clearing "deno.path" config causes lsp to not start

[dsherret]

Describe the bug

Setting then clearing the "deno.path" config setting via the GUI causes the deno extension to fail to start.

To Reproduce

1. Open up the GUI settings editor and add a user setting for "Deno: Path"
2. Save. Then clear that value.

Expected behavior

A clear and concise description of what you expected to happen.

Output

Activating extension 'denoland.vscode-deno' failed: Unsupported server configuration {
    "run": {
        "command": "",
        "args": [
            "lsp"
        ],
        "options": {
            "env": {
               // omitted
            }
        }
    },
    "debug": {
        "command": "",
        "args": [
            "lsp"
        ],
        "options": {
            "env": {
               // omitted
            }
        }
    }
}.

Couldn't start client Deno Language Server

Versions

vscode: 1.57.1 deno: 1.11.0 extension: 3.6.1