ESM support breaks custom validator initialization

[pibi]

Prerequisites

Please answer the following questions for yourself before submitting an issue.

• I am running the latest version
• I checked the documentation and found no answer
• I checked to make sure that this issue has not already been filed
• I'm reporting the issue to the correct repository

Current Behavior

When requiring the base module to setup a custom validator, node v16.14.2 throws an exception with moleculer 0.14.21:

Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './src/validators/base' is not defined by "exports" in /project/node_modules/moleculer/package.json

see below for a full log. Works correctly with moleculer 0.14.20

Expected Behavior

Should correctly require the module. For fully custom validator support we also need the following requires to work:

const BaseValidator = require("moleculer/src/validators/base");
const FallbackValidator = require("moleculer/src/validators/fastest");
const {ValidationError} = require("moleculer/src/errors");

All these do not work with 0.14.21

Steps to Reproduce

With moleculer v.014.21:

1. open a node v16.x CLI
2. require("moleculer/src/validators/base");
3. see the exception error

Failure Logs

Welcome to Node.js v16.14.2.
Type ".help" for more information.
> const BaseValidator = require("moleculer/src/validators/base");
Uncaught:
Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './src/validators/base' is not defined by "exports" in /project/node_modules/moleculer/package.json
    at __node_internal_captureLargerStackTrace (node:internal/errors:464:5)
    at new NodeError (node:internal/errors:371:5)
    at throwExportsNotFound (node:internal/modules/esm/resolve:453:9)
    at packageExportsResolve (node:internal/modules/esm/resolve:731:3)
    at resolveExports (node:internal/modules/cjs/loader:482:36)
    at Function.Module._findPath (node:internal/modules/cjs/loader:522:31)
    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:919:27)
    at Function.Module._load (node:internal/modules/cjs/loader:778:27)
    at Module.require (node:internal/modules/cjs/loader:1005:19)
    at require (node:internal/modules/cjs/helpers:102:18) {
  code: 'ERR_PACKAGE_PATH_NOT_EXPORTED'
}

[pibi]

Fixed at our side by importing right from moleculer:

const { Validators, Errors: { ValidationError } } = require("moleculer");

see: pibi/moleculer-json-schema-validator@d574f04