Updated FB import (#6019)

Previous FB import was based on the original early TS implementation
and did not take into accout NPM. There doesn't seem to be a use
for current implemenentation anymore, while NPM compatibility is
needed.

Co-authored-by: Kamil Rojewski <kamil.rojewski@gmail.com>

src/idl_gen_js_ts.cpp

@@ -214,7 +214,7 @@ class JsTsGenerator : public BaseGenerator {
          ++it) {
       if (lang_.language == IDLOptions::kTs) {
         if (it->find('.') == std::string::npos) {
-          code += "import { flatbuffers } from \"./flatbuffers\"\n";
+          code += "import * as flatbuffers from 'flatbuffers';\n";
           break;
         }
       } else {