Remove trace in adaptBoxed

[mbovel]

The project currently doesn't clean compile with tracing enabled because there is a return in a trace block in CheckCaptures.scala, which is a non-local return when tracing is enabled.

[info] compiling 595 Scala sources and 8 Java sources to /localhome/bovel/scala3/compiler/target/scala-3.6.4-RC1/classes ...
[warn] -- Warning: /localhome/bovel/scala3/compiler/src/dotty/tools/dotc/cc/CheckCaptures.scala:1387:14 
[warn] 1387 |              return actual
[warn]      |              ^^^^^^^^^^^^^
[warn]      |Non local returns are no longer supported; use `boundary` and `boundary.break` in `scala.util` instead
[error] No warnings can be incurred under -Werror (or -Xfatal-warnings)
[warn] one warning found
[error] one error found
[error] (scala3-compiler / Compile / compileIncremental) Compilation failed
[error] Total time: 26 s, completed Mar 13, 2025, 10:09:01 AM

Interestingly, first compiling with tracingEnabled = false and then switching to true works 🤔