Fix (future) declaring TS types for scalars that extend other scalars

They don't have a previous entry to modify.

Author: CarsonF

src/core/edgedb/generator/scalars.ts

@@ -1,5 +1,6 @@
 import { scalarToLiteralMapping } from '@edgedb/generate/dist/genutil.js';
 import { mapEntries } from '@seedcompany/common';
+import { set } from 'lodash';
 import { codecs } from '../codecs';
 
 export const customScalars = mapEntries(codecs, (codec) => [
@@ -11,6 +12,6 @@ export function setTsTypesFromOurScalarCodecs() {
   // this is used for schema interfaces & query builder
   for (const { info } of codecs) {
     const fqName = `${info.module}::${info.type}`;
-    scalarToLiteralMapping[fqName].type = info.ts;
+    set(scalarToLiteralMapping, [fqName, 'type'], info.ts);
   }
 }