Problems when starting debug from status line

[weinand]

When the launch config is run from the status bar:

• no launch config errors show up, e.g. if the debug type is wrong or if 'request' attribute is missing
• the same launch config can be started multiple times

I suggest to use the identical code for launching from the status line and through the debug drop down menu.

[isidorn]

One is an action, and the other is a quick open item entry. Due to that it is not very trivial to share an implementation. THough I have tried to sharae by introducing a statis isEnabled

[weinand]

Verified ok but I've created #39707 to improve the weak UI.