Fix condition to set penalty function

[snow54]

Proposed Changes

Give a brief overview of your contribution here in a few sentences.
When (Objective < Value ) * Scale ('<' can be '>') is added to OPT_OBJECTIVE in the configuration file, it is treated as a penalty function. When the constraint is satisfied, the penalty function value should be zero. However, it is currently set to the function value. The same elif condition as in obj_dp should be used.

Related Work

Resolve any issues (bug fix or feature request), note any related PRs, or mention interactions with the work of others, if any.
Resolve #1968.

PR Checklist

Put an X by all that apply. You can fill this out after submitting the PR. If you have any questions, don't hesitate to ask! We want to help. These are a guide for you to know what the reviewers will be looking for in your contribution.

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[pcarruscag]

Makes sense thanks.