Bazel build implementation, doesn't provide options for the compilation modes opt and debug.

[NolanBrad]

The Bazel toolchain implementation does not have default args for the compilation modes opt and debug
i,e --compilation_mode=dbg and --compilation_mode=opt

Also the rule "@pico-sdk//bazel/toolchain:override_debug" provides defaults of -Og and -g3, but these are enabled by default in the toolchains, and are not changed with the above bazel cmd line --compilation_mode

From the bazel docs the defaults for opt should be -O2 and -DNDEBUG
https://bazel.build/docs/user-manual#compilation-mode