Don't require equality_comparable in putParameter

[ianna]

Fixes the build against recent EDM4hep, where edm4hep::utils::ParticleIDMeta is no longer std::equality_comparable (its algoType member became private, removing the defaulted operator==). putParameter required that concept only for the *existing == value comparison behind skipIfSameValue().

This relaxes the template constraint and guards the comparison with if constexpr (std::equality_comparable<T>). For non-comparable metadata types the "skip if identical value" shortcut is bypassed; all other behaviour is unchanged.

BEGINRELEASENOTES

• Fix compilation of putParameter with metadata types that are not std::equality_comparable (e.g. edm4hep::utils::ParticleIDMeta in recent EDM4hep). The skipIfSameValue() optimization is now only applied when the type supports ==.

ENDRELEASENOTES

[ianna]

@jmcarcell and @andresailer - this should allow all tests pass for #372

[jmcarcell]

That has already been fixed in EDM4hep: key4hep/EDM4hep#497 but that change is not in the latest tag/release. The change here would silently ignore anything that doesn't have a operator== defined instead of failing at compile-time.