[RLC from swagger] Update source files with js suffix in imports

[MaryGao]

Similar to this commit, during RLC generation from swagger, we should update the imports with js suffix for esm importing. Once succeess, the relevant files should be updated correctly.

From

import {
  ReadonlypropertyPutValidDefaultResponse,
  FlattencomplexGetValid200Response,
} from "./responses";

To

import {
  ReadonlypropertyPutValidDefaultResponse,
  FlattencomplexGetValid200Response,
} from "./responses.js";