Temporarily downgrade gradle module language level

[mbien]

• resolves a "Project Problems" regression
• temporary until proper fix is implemented

fixes #7365 ~? untested~

[ebarboni]

do we let the exception throw ?

[lkishalmi]

do we let the exception throw ?

Well, that default part should not happen. The new switch checks for completeness. Reverting back to the old syntax and trying to be complete would add a default case.

I'm going to split the Gradle module for NB23, as it seems we need some parts kept on Java 8 level for a while, while the majority of code would be fine on Java 17.

[neilcsmith-net]

Yes, there's a synthesized default that throws an exception in the current code - no difference IMO.

@lkishalmi yes, it also makes sense to isolate any class that might be sent over the wire into the daemon process anyway, source level or not?