fix(bundle.go): validate param regardless of if override or default

[vdice]

• Fixes a bug wherein we weren't previously validating a parameter if we inherit the default. Now we validate regardless of where we inherit the parameter from (e.g. an override or a default).

[vdice]

Maybe as a follow-up we can check when we validate the bundle?

Good call! Will do.

Edit: Here is the follow-up: https://github.com/cnabio/cnab-go/pull/254