DIAG_COORD_DEF_RHO2 is not been set for tx2_3v3

We missed setting DIAG_COORD_DEF_RHO2 for tx2_3v3 (see [here](https://github.com/ESCOMP/MOM_interface/blob/5720051b95c9c470d3aad1b88b2556994bb58793/param_templates/MOM_input.yaml#L1364C27-L1364C34)), so the default value (WOA09) was used instead. As a result, the rho2 diagnostics are incorrect and not meaningful. This issue only affects the rho2 diagnostics.