fix(snix/boot/tests): fix otlp error

Fixes a non-critical error when running a boot test.
All boot tests worked before too, so it was nothing more than a noise,
though I think worth addressing anyway.

> mg build //snix/boot/tests:docs-persistent

2025-08-10T11:59:31.068658Z ERROR opentelemetry_sdk:  name="BatchSpanProcessor.ExportError" error="Operation failed: status: Unavailable, message: \"tcp connect error: Connection refused (os error 111)\", details: [], metadata: MetadataMap { headers: {} }"
failed to shutdown tracing: Operation failed: errs: [Err(InternalFailure("Operation failed: status: Unavailable, message: \"tcp connect error: Connection refused (os error 111)\", details: [], metadata: MetadataMap { headers: {} }"))]

Change-Id: I2722f814f7cfea42e50efe71106e6809ea66ef81
Reviewed-on: https://cl.snix.dev/c/snix/+/30675
Tested-by: besadii
Reviewed-by: Florian Klink <flokli@flokli.de>

snix/boot/tests/default.nix

@@ -90,7 +90,7 @@ let
         + lib.optionalString (!isClosure) ''
           echo "Importing ${path} into snix-store with name ${importPathName}…"
           cp -R ${path} ${importPathName}
-          outpath=$(snix-store import ${importPathName})
+          outpath=$(snix-store --otlp=false import ${importPathName})
 
           echo "imported to $outpath"
         ''