Drop PC search for entityReference for input tokens not recognized by validator.

[jvwong]

In landing-box.js the function getLandingResult calls pcFallback (essentially a PC web service call to Search) to try and map input tokens that weren't recognized by the validator service as genes.

const getLandingResult= (query)=> {
...
  }).then(genes=>Promise.all(pcFallback(genes.unrecognized,genes)).then(()=>genes)).then((genes)=>{
     ...
};

However, the result from pcFallback is rather non-specific (returns first UniProt hit) so basically returns garbage in some cases: Look at search for 'signaling'.

Suggest to remove Remove the call to pcFallback in getLandingResult. It's returning garbage to the info box.