Remove expansion term from recoil pressure

[hepap]

Description of the problem

• Recoil pressure formulation 0.55p_sat + [1/rho]m_dot^2 was accounting 2 time the [1/rho]m_dot^2 because the latter is included in the term 0.55p_sat.

Description of the solution

• Remove it, the formulation is now 0.55*p_sat

How Has This Been Tested?

• no test has changed

Documentation

• no documentation has changed

Future changes

• Add test and doc for evaporation model

[blaisb]

@hepap could you add the information to the CHANGELOG?

[blaisb]

@hepap can you rebase, then I can merge once CI passes? Thx

[hepap]

@blaisb done :)