firefoxExecutable ignored

Trying to get debugging working on Windows 10/64 for Thunderbird extension, but will only launch Firefox. I have tried the path as shown below and `"C:\\Program Files (x86)\\Mozilla Thunderbird New\\thunderbird.exe"`
Here's the config:

```
{
"name": "Thunderbird",
"type": "firefox",
"request": "launch",
"reAttach": true,
"firefoxExecutable": "C:/Program Files (x86)/Mozilla Thunderbird New/thunderbird.exe",
"reloadOnChange": {
"watch": "${workspaceFolder}/*.js",
},
"profileDir": "C:/Users/DevWin10/AppData/Roaming/Thunderbird/Profiles/tyyl1700.Test User",
"keepProfileChanges": true,
"internalConsoleOptions": "openOnSessionStart",
"addonPath": "${workspaceFolder}/"
},
````

Reproduce the Windows 10/64 launch using the supplied Thunderbird configuration, especially the firefoxExecutable and profileDir values. Trace how that configuration selects the executable, then verify that a debug session launches Thunderbird rather than Firefox.

Written by the indexing model from the issue text.