Add a property to launch.json to specify the location of the lldb-dap to use

[tedwoodward]

Some users, especially embedded developers, switch between toolchains frequently. Currently, the lldb-dap extension allows this by changing a setting in the extension, but this is cumbersome if a user switches frequently on a per-project basis.

Add a property to configurations for lldb-dap in launch.json to specify the location of the lldb-dap executable to use, overriding the setting in the extension for that configuration. If the property does not exist, use the setting in the extension.

[vogelsgesang]

Afaict, this was addressed by #126803. If that is not the case, please reopen the issue