Remove old/unused warning from jsifier (#20298)

I'm fairly sure this no longer correct and doesn't fire in any
of our test code.

This warning only fires for library members that are of type 'string'
for some reason (as of 1ddb637), and
since library members with deps are almost universally functions I've
never seen it fire.

Author: sbc100

src/jsifier.js

@@ -428,11 +428,9 @@ function(${args}) {
       const original = LibraryManager.library[symbol];
       let snippet = original;
 
+      // Check for dependencies on `__internal` symbols from user libraries.
       const isUserSymbol = LibraryManager.library[symbol + '__user'];
       deps.forEach((dep) => {
-        if (typeof snippet == 'string' && !(dep in LibraryManager.library)) {
-          warn(`missing library dependency ${dep}, make sure you are compiling with the right options (see #if in src/library*.js)`);
-        }
         if (isUserSymbol && LibraryManager.library[dep + '__internal']) {
           warn(`user library symbol '${symbol}' depends on internal symbol '${dep}'`);
         }