pw_ide: Include default output group for Rust project generation

When bazel_args includes flags like --config=k_lint which override
output_groups (e.g. to clippy_checks,rustfmt_checks), Bazel omits
the default executable binary for @rules_rust//tools/rust_analyzer:gen_rust_project.
This caused gen_rust_project to fail at execution time with a missing
binary error.

This change appends --output_groups=+default when pw_ide runs
gen_rust_project, ensuring the executable binary is compiled even
when lint flags are present in bazel_args.

Change-Id: Ic1e6a37c1d7364f8ed3b4d13ea50663d3e5578d1
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/450012